Marketing Sustainable Fashion: Trends and Future Directions

: The fashion industry is one of the largest contributors to greenhouse gas emissions and climate change. Sustainable fashion (SF) aims to address this issue by designing, creating, and marketing socially and environmentally responsible products. This paper provides a broad overview of the extant literature on SF marketing to understand the trends and future directions. The paper starts with a discussion on sustainable consumption and marketing in the particular context of fashion and ends with potential research gaps, which have scope for further work. For the analysis, 97 research papers were selected based on a structured, systematic search with a particular set of keywords. The review ﬁnds that marketing SF from a customer’s perspective has been emphasized in the existing literature. Widely studied topics include consumer behavior, purchase behavior, and the attitude– behavior gap. Further research is required to explore how SF can gain from B2B marketing, circular economy, sustainability-oriented innovations, and subsistence markets, particularly in emerging economies. This paper contributes to theory and practice by providing state-of-the-art sustainable fashion marketing research, identifying research gaps, and providing future research directions.


Introduction
Sustainability has become one of the most discussed topics in academia and industry.It became a popular term in the late 1980s, with the world realizing the importance of depleting natural resources and the need for sustainable development.The Brundtland Report defines sustainable development as "a kind of development which satisfies the needs of the present without compromising the ability of future generations to satisfy their needs" [1,2].Sustainability is a relationship between human demands and productive capacity across time, as well as a relationship between human welfare at various phases of development [3].With the growing pace of industrialization and climate change, environmental degradation has reached alarming proportions.A warming planet, untimely cyclones, frequent draughts, the melting of glaciers, and depleting green cover are major consequences of climate change.The fashion industry adds to these issues with high consumption, waste generation/disposal, and unsustainable practices.Conspicuous consumption has led to the extraordinary growth of the fast fashion industry.It affects ecological sustainability, social equity, and economic sustainability.The effective marketing of SF is a potential answer to all these issues.This paper is based on two primary research questions: (i) What do we know about the marketing of SF? and (ii) How can marketing facilitate the popularization and mainstreaming of SF?The systematic literature review in this paper addresses these questions, identifies research gaps, and provides directions for future research.
This paper first discusses the theoretical background of sustainability, climate change, and marketing.It then discusses the role and impact of fashion marketing and sustainability.Section 3 presents the methodology of the literature review and analysis.Both descriptive and thematic analyses of the literature are presented next in the Section 4. The thematic analysis section summarizes key themes and sub-themes based on the extant literature.Next, the research questions are addressed by analyzing the extant literature in the Section 5.
The future research directives and implications for theory and practice are discussed in the same section.The paper ends with the conclusion and limitations of this review.

Sustainability, Climate Change, and Business
Climate change is the negative consequence of unsustainable human activities leading to shifts in ecological settings.Post-industrial revolution, technological disruption, and automation have led to ecological imbalance and social inequity.Thus, climate change and business are interrelated.The physical risks of climate change challenge the existing supply chains, business models, and decision-making [4].It also affects the socio-economic conditions of marginalized groups.Such a situation makes sustainable business models and practices essential for the collective benefit of the people, planet, and profit.Traditional business models considered linear value exchange among the stakeholders where the benefit was limited to a few.However, sustainable business models target stakeholders' direct and dual involvement, especially the consumers, while creating sustainable value [5][6][7].Incorporating sustainability in the business model ensures cleaner energy usage and emphasizes repair and reuse instead of discarding and disposal.Businesses also act as agents to accomplish sustainable development [8].

Marketing and Sustainability
Marketing operates on the principle of the transaction of values among two parties, where values can be goods, services, money, time, energy, and feelings [9].It creates, communicates, and delivers customer value while meeting profit targets.Recognizing and integrating these customer needs into the firm's value proposition is crucial in designing an efficient and sustainable business model [10].Businesses adopt innovative marketing strategies to accommodate sustainability objectives in their business models.
Marketing is also a key influencer of consumer behavior, attitude, and beliefs.A proper marketing strategy can promote sustainable behavior and nudge consumers towards sustainable purchase behaviors [11,12].For instance, leading clothing company Patagonia's promotion campaign 'Don't buy this jacket' prompted consumers to re-think their buying practices and consider repairing their old Patagonia items [13].Marketing can be a game changer to impart sustainability to business, not just in promotions but also in other domains starting from ideation to sales.Marketing also plays a crucial role in achieving SDGs by facilitating responsible consumerism and business practices [14].
Another school of thought criticizes marketing for the growth of fast fashion, mindless buying behavior, and even greenwashing, which involves overstated, false, or unfounded claims about the environmental benefits of products/services [15].To keep up with the sales targets, brands may use broad and ambiguous terms/statements, such as 'fair', 'made with love', and 'green', to create a perception that they are associated with sustainability [16].Brands are also involved in a practice known as "bluewashing", where they pay lip service to the actual goals of corporate social responsibility (CSR) instead of the practical and worthy implementation of CSR goals [17].As discussed above, marketing can and should go beyond such practices and move to 'better marketing for a better world' [18].

Role of Fashion in Sustainability
Fashion is a popular way, or the latest way, of clothing, hair, decoration, or behavior based on a particular period, place, and context [19,20].It is a way of self-expressing and culturally constructing the embodied identity [21].Driven by social demands, fashion recurrently changes social forms, clothing habits, aesthetic judgment, and the entire style of human expression [22].It thus is a product designed by social demands and has a considerable influence on society, especially the upper class and the female population [23].Fashion includes apparel, jewelry, footwear, and other accessories [24].However, this paper focuses only on apparel/clothes/textiles.The industry faces an ever-growing demand on a global basis to keep up with the consumers' need for new things in their lives.Globally, the fashion industry employs a large workforce, creating a significant economic and social impact.However, it also faces criticism for its negative effect on ecology and social equity.
Fast fashion refers to the practice of quickly producing popular designs at a low cost.It has increased the system's material throughput, producing abundant, low-cost clothes.Low-cost clothes do not last long and are discarded faster, adding to the problem of waste.By adopting sustainable activities and fair trade practices, fashion can contribute to the SDGs by minimizing energy consumption, lessening and improving the use of natural resources and water, lessening load on landfills, and reducing toxic chemicals used [25].Eventually, reducing the negative impacts of the fashion industry depends on a total shift from the fast fashion model and the adoption of a more circular model [26].Fashion in many spheres is considered a luxury, with high-end brands coming in with the latest trends.Most buyers believe luxury should not be a priority for sustainability [27].Fashion consumerism and purchase behavior, thus, act as crucial influencers in achieving sustainability, particularly in the apparel industry.

Sustainable Fashion
Sustainability in the fashion industry became a familiar term after the 1992 Rio Earth Summit.Brands started looking for ways to reduce their negative impact on the planet and the people.SF is based on and adopts sustainability in any/all of the stages of its lifecycle, reducing the harsh effects on the environment and biodiversity while being socially responsible.Sustainable fashion as a phrase seems like an oxymoron [28] because fashion comes with a short shelf life and updates with seasonal trends, whereas sustainability is synonymous with longevity and long-term product usage.SF is a subset of the slow fashion movement, and the terms eco-, green-, and ethical-fashion are generally used synonymously [29].Sustainable apparel poses a minimal adverse effect on the environment and society in its entire product lifecycle, from production, usage, disposal, and degradation.

Marketing of SF
Proper marketing of sustainable apparel can act as an enabler for sustainable clothes purchases [30].Marketing SF typically manages product flow from initial design selection through production to product presentation to retailers [19].SF marketing can be studied broadly in two ways based on the end-users targeted: a.
B2C marketing refers to the marketing activities directed at the end-consumers of a product or service [19,24].Fashion brands sell their products primarily in a B2C market, through online and offline retailing.Demand and consumer behavior are the main driving forces for B2C marketing [31].For fashion B2C marketing, the primary challenge is to keep up with the latest trends.Higher prices and lower accessibility of SF act as two of the most significant obstructions to SF consumption [32][33][34][35][36][37][38].
B2B marketing refers to the marketing activities directed at organizational buyers [19,24].Fashion brands can sell their products to other organizations, e.g., corporate gifting purchases and uniforms.A few examples of B2B companies in the apparel industry are FashionablyIn (connects fashion houses to factories and suppliers), Sauvecotton (offers fashion materials), and Wholsesalebox (an online wholesale distribution platform for fashion products).The second aspect of fashion B2B marketing involves procuring sustainable raw materials and technology.For example, a technology that allows for the waterless dyeing of fabric can reduce the water footprint of a fashion brand.Green supply chain management is a significant factor in the B2B marketing of SF.The key concerns here are the cost and flow of resources [39].SF can flourish only when SF brands are provided with an affordable choice of green raw materials and technologies.However, B2B markets have received a limited research focus in the extant literature [40].

Systematic Literature Review (SLR) Methodology
This research employs a systematic review to summarize the sustainable fashion marketing literature.A systematic review is a structured, precise, and reproducible method for ascertaining, assessing, and integrating the extant body of work by academics and industry professionals [41].It follows a bias-free, transparent and reproducible method of searching the existing literature, screening it, and identifying gaps [42,43].Following the guiding principles of SLR, a four-step process was adopted [44] for the literature synthesis.The methodology can be summarized into key steps in Figure 1.
chain management is a significant factor in the B2B marketing of SF.The key concerns here are the cost and flow of resources [39].SF can flourish only when SF brands are provided with an affordable choice of green raw materials and technologies.However, B2B markets have received a limited research focus in the extant literature [40].

Systematic Literature Review (SLR) Methodology
This research employs a systematic review to summarize the sustainable fashion marketing literature.A systematic review is a structured, precise, and reproducible method for ascertaining, assessing, and integrating the extant body of work by academics and industry professionals [41].It follows a bias-free, transparent and reproducible method of searching the existing literature, screening it, and identifying gaps [42,43].Following the guiding principles of SLR, a four-step process was adopted [44] for the literature synthesis.The methodology can be summarized into key steps in Figure 1.

Search for Existing Literature
This research aims to address the question, "What do we know about Marketing sustainable fashion?"Accordingly, the literature search and keywords were fixed.
We performed an extensive literature search using words related to marketing and sustainable fashion consumption to arrive at different themes and sub-themes [45].Eight electronic databases were selected for the keyword search: EbscoHost, Proquest, Science Direct, JSTOR, Emerald Insights, SAGE, J-Gate, and Taylor & Francis [14,46].A structured and iterative search was performed in these databases from August to September 2021.The keywords were used as search phrases for a better coverage of papers.The used search phrases were "marketing" AND "Sustainable Fashion" OR "sustainable fashion consumption".The terms "eco-fashion", "ethical fashion", and "green fashion" were used alternately during the search in place of "sustainable fashion", as they are used synonymously [47,48].We conducted an initial search in abstracts and titles of papers.It resulted in 530 academic papers in the initial search.

Screening
Specific inclusion and exclusion criteria were defined as part of the search strategy.First, the publications/papers included had to be in the English language.Second, peer-

Search for Existing Literature
This research aims to address the question, "What do we know about Marketing sustainable fashion?"Accordingly, the literature search and keywords were fixed.
We performed an extensive literature search using words related to marketing and sustainable fashion consumption to arrive at different themes and sub-themes [45].Eight electronic databases were selected for the keyword search: EbscoHost, Proquest, Science Direct, JSTOR, Emerald Insights, SAGE, J-Gate, and Taylor & Francis [14,46].A structured and iterative search was performed in these databases from August to September 2021.The keywords were used as search phrases for a better coverage of papers.The used search phrases were "marketing" AND "Sustainable Fashion" OR "sustainable fashion consumption".The terms "eco-fashion", "ethical fashion", and "green fashion" were used alternately during the search in place of "sustainable fashion", as they are used synonymously [47,48].We conducted an initial search in abstracts and titles of papers.It resulted in 530 academic papers in the initial search.

Screening
Specific inclusion and exclusion criteria were defined as part of the search strategy.First, the publications/papers included had to be in the English language.Second, peerreviewed ABDC-listed marketing journals were referred to during article selection, which is in line with SLRs published in marketing journals [14].A few domain-specific journals, such as Sustainability and Fashion Theory, were also referred to as an exception due to their content related to fashion and sustainability.Third, the publication timeline was set as 1987-2021, considering the publication year of The Brundtland Report, 1987, and the time when SF received public attention [47].Fourth, duplicate results that appeared more than once in the search result of different databases were eliminated.A detailed PRISMA flowchart, as used in other published literature review papers [44], is depicted in Figure 2, showing the steps and criteria followed.
reviewed ABDC-listed marketing journals were referred to during article selection, which is in line with SLRs published in marketing journals [14].A few domain-specific journals, such as Sustainability and Fashion Theory, were also referred to as an exception due to their content related to fashion and sustainability.Third, the publication timeline was set as 1987-2021, considering the publication year of The Brundtland Report, 1987, and the time when SF received public attention [47].Fourth, duplicate results that appeared more than once in the search result of different databases were eliminated.A detailed PRISMA flowchart, as used in other published literature review papers [44], is depicted in Figure 2, showing the steps and criteria followed.

Eligibility Criteria
The selection of papers for the review was based on three eligibility criteria.First, papers that did not discuss marketing and sustainable fashion concepts were excluded based on reading their title and abstracts.Second, a full-text reading of the articles by both authors gave an idea about the topic covered in the paper.Third, the papers that were unavailable in their full-text form were eliminated.Next, papers were evaluated and organized in a data extraction excel sheet based on variables, theories, research objectives, methodology, results, and future research scope.Fifth, only research articles and book chapters were considered; one viewpoint article in the search results was included as it was relevant to SF.

Inclusion
Papers that did not align with the research objective and questions were removed after detailed readings of the papers.Finally, 97 papers were selected for this literature review.The literature captured was classified into themes and sub-themes based on their contribution, and an analysis of potential gaps was performed and summarized.

Eligibility Criteria
The selection of papers for the review was based on three eligibility criteria.First, papers that did not discuss marketing and sustainable fashion concepts were excluded based on reading their title and abstracts.Second, a full-text reading of the articles by both authors gave an idea about the topic covered in the paper.Third, the papers that were unavailable in their full-text form were eliminated.Next, papers were evaluated and organized in a data extraction excel sheet based on variables, theories, research objectives, methodology, results, and future research scope.Fifth, only research articles and book chapters were considered; one viewpoint article in the search results was included as it was relevant to SF.

Inclusion
Papers that did not align with the research objective and questions were removed after detailed readings of the papers.Finally, 97 papers were selected for this literature review.The literature captured was classified into themes and sub-themes based on their contribution, and an analysis of potential gaps was performed and summarized.

Findings
An N X N matrix (see Figure ??) was designed based on the papers' primary focus areas and their influencing factors.This matrix classifies the literature related to SF and sustainable consumption into various marketing domains.Multiple themes and sub-themes were listed based on this matrix.It might not be fully exhaustive and has some expected overlaps.However, this gives an overall picture of the existing research and where further research can be conducted.

Descriptive Analysis
The articles/papers are broadly of two types based on their nature of work: conceptual and empirical.Around 82 papers have followed empirical methods to address their research questions.Rest 13 papers were conceptual articles, including literature reviews and theoretical papers.Figure 4 depicts the percentage distribution of the papers based on their research approach.

Descriptive Analysis
The articles/papers are broadly of two types based on their nature of work: conce tual and empirical.Around 82 papers have followed empirical methods to address th research questions.Rest 13 papers were conceptual articles, including literature review and theoretical papers.Figure 4 depicts the percentage distribution of the papers bas on their research approach.The number of publications shows an increasing trend from 2006 until 2021.Ho ever, there was a dip from 2015 to 2017, and again there was an increase in the number papers post-2017.Figure 5 indicates that this area is an upcoming and exciting resear area for researchers.Most of the publications are from the "Journal of Fashion Marketing and Managemen (JFMM), followed by the "Journal of Business Research" (JBR) and the "Journal of Global Fa ion Marketing" (JGFM).The papers selected were from various journals ranging from Co sumer behavior-, retail, fashion-, and business-research-based areas.Most of the public  The number of publications shows an increasing trend from 2006 until 2021.However, there was a dip from 2015 to 2017, and again there was an increase in the number of papers post-2017.Figure 5 indicates that this area is an upcoming and exciting research area for researchers.

Descriptive Analysis
The articles/papers are broadly of two types based on their nature of work: conceptual and empirical.Around 82 papers have followed empirical methods to address their research questions.Rest 13 papers were conceptual articles, including literature reviews and theoretical papers.Figure 4 depicts the percentage distribution of the papers based on their research approach.The number of publications shows an increasing trend from 2006 until 2021.However, there was a dip from 2015 to 2017, and again there was an increase in the number of papers post-2017.Figure 5 indicates that this area is an upcoming and exciting research area for researchers.Most of the publications are from the "Journal of Fashion Marketing and Management" (JFMM), followed by the "Journal of Business Research" (JBR) and the "Journal of Global Fashion Marketing" (JGFM).The papers selected were from various journals ranging from Consumer behavior-, retail, fashion-, and business-research-based areas.Most of the publications with more than 200 citations were from the JFMM.The highest cited paper was from the "Asia Pacific Journal of Marketing and Logistics", with 690 citations.Other highly cited papers were from the "International Journal of Consumer Studies" (IJCS), "The Internationa Review of Retail, Distribution and Consumer Research" (IRRDCS), JBR, JGFM, the "Journal o Consumer Marketing" (JCM), and the "International Journal of Consumer Studies" (IJCS).Most of the publications are from the "Journal of Fashion Marketing and Management" (JFMM), followed by the "Journal of Business Research" (JBR) and the "Journal of Global Fashion Marketing" (JGFM).The papers selected were from various journals ranging from Consumer behavior-, retail, fashion-, and business-research-based areas.Most of the publications with more than 200 citations were from the JFMM.The highest cited paper was from the "Asia Pacific Journal of Marketing and Logistics", with 690 citations.Other highly cited papers were from the "International Journal of Consumer Studies" (IJCS), "The International Review of Retail, Distribution and Consumer Research" (IRRDCS), JBR, JGFM, the "Journal of Consumer Marketing" (JCM), and the "International Journal of Consumer Studies" (IJCS).

Number of papers
Interviews (33 papers, including mixed approach) and surveys (42 papers, including mixed approach) were the most used methods for data collection in qualitative and quantitative approaches.The interviews were personal, in-depth, laddering, ethnographic, and phenomenological.Some unique methods, such as participant observations with stimuli and netnographic investigations, were also considered.
Confirmatory factor analysis (CFA) and structural equation modeling (SEM) were two of the most preferred methods for quantitative data analysis.Most papers referred to behavioral theories and models, such as the Fritzsche model, social constructionist theory, Schwartz's value theory, means-end theory, and others.The theory of planned behavior is the most used model.
Most papers wrote in the context of the USA, followed by the UK and Korea.Out of the selected papers, none were found to cover African countries.Among the Asian countries, most publications were based in Korea, Japan, and China.Thus, the findings might be skewed and might not be valid for all cultures throughout the globe.
Figure 6 illustrates the number of papers in each of the selected journals.The literature is primarily spread across ABDC-listed marketing journals.Interviews (33 papers, including mixed approach) and surveys (42 papers, including mixed approach) were the most used methods for data collection in qualitative and quantitative approaches.The interviews were personal, in-depth, laddering, ethnographic, and phenomenological.Some unique methods, such as participant observations with stimuli and netnographic investigations, were also considered.
Confirmatory factor analysis (CFA) and structural equation modeling (SEM) were two of the most preferred methods for quantitative data analysis.Most papers referred to behavioral theories and models, such as the Fritzsche model, social constructionist theory, Schwartz's value theory, means-end theory, and others.The theory of planned behavior is the most used model.
Most papers wrote in the context of the USA, followed by the UK and Korea.Out of the selected papers, none were found to cover African countries.Among the Asian countries, most publications were based in Korea, Japan, and China.Thus, the findings might be skewed and might not be valid for all cultures throughout the globe.
Figure 6 illustrates the number of papers in each of the selected journals.The literature is primarily spread across ABDC-listed marketing journals.The studies are spread across five continents: Europe, North America, South America, Asia, and Oceania.Figure 7 depicts the distribution of the papers worldwide.
Most publications had the younger generation of Caucasian females as their target group.Few publications have considered a male-only target group, a not-so-young target group, and mothers as their target groups.The studies are spread across five continents: Europe, North America, South America, Asia, and Oceania.Figure 7 depicts the distribution of the papers worldwide.

Thematic Analysis
The selected papers are classified into themes and sub-themes based on their focus area of study and reported findings.Figure 9 summarizes the five prominent themes and their sub-themes that have emerged in association with the marketing of SF.Each theme Most publications had the younger generation of Caucasian females as their target group.Few publications have considered a male-only target group, a not-so-young target group, and mothers as their target groups.
The selected papers have followed quantitative, qualitative, and mixed (quantitative and qualitative) methodologies.Figure 8   The selected papers have followed quantitative, qualitative, and mixed (quantit and qualitative) methodologies.Figure 8 illustrates the research methodologies and proaches followed by the papers.Qualitative research methods (used in 40 papers most preferred.

Thematic Analysis
The selected papers are classified into themes and sub-themes based on their f area of study and reported findings.Figure 9 summarizes the five prominent themes

Thematic Analysis
The selected papers are classified into themes and sub-themes based on their focus area of study and reported findings.Figure 9 summarizes the five prominent themes and their sub-themes that have emerged in association with the marketing of SF.Each theme and sub-theme is explained with relevant citations.The number of papers supporting the themes and sub-themes is mentioned in parentheses beside the headings.and sub-theme is explained with relevant citations.The number of papers supporting the themes and sub-themes is mentioned in parentheses beside the headings.Marketing communication facilitates the consumers' association with a brand/product by educating them about the product.Retailers use marketing communications channels to ensure the successful launch of SF products.Consumers are unaware of the SF production process and whether it is produced in an ethical/environmentally friendly way or not.Thus, consumer education is essential for raising awareness about SF.Despite low awareness, some consumers still pay premium for SF.Proper promotion and branding can influence more consumers to move towards SF.Corporate marketing information, effectiveness, and social knowledge are essential in forming an attitude toward sustainable fashion products.Fashion brands can incorporate effective sources and types of sustainable knowledge into their marketing strategies to expand their business scope [49].
Sub-Theme 1: Promotion of SF (8 Papers) Promotions are a combination of activities that inform the target audiences about a product's features, attributes, and services.The promotional mix includes sales promotion, advertising, personal selling, public relations, and direct marketing [9].Social media is the most effective platform for promotions in this digital era.Celebrity entrepreneurs raise awareness of SF consumption and influence mainstream apparel consumers towards  Marketing communication facilitates the consumers' association with a brand/product by educating them about the product.Retailers use marketing communications channels to ensure the successful launch of SF products.Consumers are unaware of the SF production process and whether it is produced in an ethical/environmentally friendly way or not.Thus, consumer education is essential for raising awareness about SF.Despite low awareness, some consumers still pay premium for SF.Proper promotion and branding can influence more consumers to move towards SF.Corporate marketing information, effectiveness, and social knowledge are essential in forming an attitude toward sustainable fashion products.Fashion brands can incorporate effective sources and types of sustainable knowledge into their marketing strategies to expand their business scope [49].
Sub-Theme 1: Promotion of SF (8 Papers) Promotions are a combination of activities that inform the target audiences about a product's features, attributes, and services.The promotional mix includes sales promotion, advertising, personal selling, public relations, and direct marketing [9].Social media is the most effective platform for promotions in this digital era.Celebrity entrepreneurs raise awareness of SF consumption and influence mainstream apparel consumers towards SF.Their Instagram accounts encourage consumer discussions on SF; however, it has no significant impact on SF purchases [50].Digital consumers look for exciting and aesthetically attractive posts.They engage with posts on fashion and lifestyle.Other engaging themes on social media are sustainability, philanthropy, social awareness, current events, branding, promotion/sale, celebrity, memes, art, animals, food, and beauty.Consumers' engagement with SF brands differs from traditional fashion brands, particularly for Instagram followers [51].They are more likely to be influenced towards SF when promoted on social media than when conventional fashion is promoted on the same platform.
Promotional activities can help in breaking the stereotype associated with SF.According to the extant literature, there is a negative association between sustainability and fashion awareness.The latter may reduce the influence of sustainable fashion's perceived value on brand affect/trust while increasing the impact of fast fashion's perceived value on brand affect/trust [52].Advertising should be explicit about eco-friendly products to influence consumers to form a positive attitude towards apparel brands [53].The eco-friendly messages in the ad for luxury products create a more positive impact on consumers' behavioral intentions when compared to eco-friendly messages in ads for conventional products [54].A positively framed message in an advertisement can bring a positive attitude in the SF purchase behavior.However, this works only when it is targeted to the correct audience.SF adverts are most effective for consumers with pro-social behavior, empathy, and high agreeableness [55].Thus, a proper combination of an SF advertising plan and target audience is required for promoting SF.The subjective norm, attitude toward advertisements, involvement in eco-fashion, and environmental dedication are some of the most significant indicators of the desire to purchase eco-friendly clothing.The effect of advertising for a new sustainable product is significant if advertised with a reputed certification.Trust in certification also positively impacts the attitude towards SF and buying intention [56].Thus, marketers can leverage certifications for advertising sustainable fashion.

Sub-Theme 2: Branding of SF (12 Papers)
A brand is "a name, symbol, design, term or any other feature that categorizes one seller's goods or service as discrete from those of other sellers" [57].Branding is a process to make the consumer identify or associate a brand with some feature [58].Consumers form a brand identity and positioning based on what and how the message is communicated, gradually leading to their purchase intentions [59].Perception of sustainability has a positive effect on brand attitude, and trust has a positive impact on brand evaluation.Economic and social sustainability information in social media brand posts motivates electronic word-of-mouth for luxury fashion brands.However, environmental and cultural sustainability influences the buying intentions of non-luxury brands [60].There seems to be a strategic misalignment between the apparel consumers' expectations and how eco-apparels are currently being marketed.Selling eco-apparel through limited distribution channels has made products less visible, and has created opportunities for spreading misleading information.A strategic profile has to be adopted with general directions on which value could be eliminated, raised, reduced, or created for extending eco-apparel to a broader segment of the apparel market [61].
To properly position SF brands, companies must highlight products and practice authenticity, regional or traditional product elements, including their design and history [62].Transparency in the procurement of raw materials and the production process (for example, organically grown cotton) can also help eco-fashion brands to establish their credibility.They must ensure their purposes go beyond the aesthetic aspects of branding and marketing [63].Customer equity increases with growing customer happiness with the sustainability of fashion products.When customers perceive sustainable performance, they are more satisfied and are less inclined to stop using the brand.As a result, they will develop higher brand equity and relationship equity with the SF brand [64].
Certain "muted sustainable brands" operate sustainably but prefer not to communicate their efforts to consumers [59].This results from the marketplace's power structures, which are crucial in shifting the postmodern branding paradigm.Apparel brands can be either proactive (i.e., eco-friendly fashion brands) or reactive (i.e., fast fashion brands) based on their perspective regarding sustainability.Consumers develop brand loyalty for each kind of brand in different ways.For SF brands, consumers with higher sustainability knowledge tend to develop a strong positive association between perceived brand value and brand trust.This association becomes weaker for fast fashion brands with higher sustainability awareness [52].It shows that "proactive" apparel brands need better marketing communications to generate and sustain brand trust.
The impact of fashion brand marketers' messages is frequently ambiguous, dispersed, and more likely to result in user frustration than positive consumer decision-making.It occurs due to a lack of knowledge and grasp of key green language terminology often used in fashion marketing communication [65].This, in turn, affects brand knowledge and brand loyalty.Sustainable activities in the conventional fashion market positively influence brand image, satisfaction, trust, and loyalty [66].While purchasing a product with a green logo, consumers' inclination for SF products increases if exposed to environmental priming messages before buying [11].Thus, a "nudge" communication can reinforce the link between sustainability beliefs and actual behavior.The verbal and visual nudge substantially and positively affects SF's choice and willingness to pay [12].Based on the earlier brand perception of a fast fashion brand, consumers can have a positive attitude toward sustainability-oriented brand extension.When offering sustainable products, marketing communication should highlight the brand's potential compatibility with the cause of sustainability.While doing so, brand marketers should also consider the consumers' familiarity with the brand and its mission [30].

Theme 2: Product Specifications (21 Papers)
SF as a 'product' has received significant attention from researchers, most of which focuses on fast fashion and slow fashion.Slow fashion does not just mean reducing fashion consumption/production, it also means preserving the welfare of the stakeholders along the supply chain and product lifespan [67].The manifestation of the sustainability focus can distinguish slow fashion practices anywhere along the supply chain and product lifespan [68].
Sub-Theme 1: 'Ethical Fashion' Definitions and Attributes (6 Papers) Organizations equate specific attributes, such as ethical design, upcycling, and innovation, to their priorities and flexibilities to define sustainable/ethical fashion [47].Ethical fashion is being promoted in the market with the approach of "Fashion with a conscience".Brands assume conscientious consumers would choose ethical fashion over fast or conventional fashion.However, even environmentally conscious consumers tend to keep this reason aside while buying.Most consumers are worried more about their fashion requirements than the ethical considerations or other stakeholders in the fashion supply chain [69].The constructs of the "Theory of planned behavior", i.e., attitude, subjective norm, and perceived behavioral control, predicts buying motives for SF, subjective norms being the most influential predictor of purchase intention [70].Product attributes and selection variety are the highest predictors of these constructs.
Contrary to common perceptions, product-related attributes do not affect SF purchase decision.Instead, store-related attributes (such as ambiance, convenience, aesthetics, etc.) positively influence consumers' SF consumption decisions, and can be further hindered by high-price premiums [39].The main obstacles to SF consumption behavior are perceptions such as lack of quality, style, good fit, fashionable selections, and trendiness [71].Fiber origin, type, and production process influence consumers' ideas regarding SF's product attributes.Consumers are more likely to buy apparel produced with locally grown fibers and using value-based labeling [72].

Sub-Theme 2: Circular Fashion Products and Circular Economy (13 Papers)
In a circular economy, all forms of waste are returned to the economy or reused efficiently, i.e., the value of the materials is maintained as long as possible [73].In a circular fashion economy, products are consumed as long as their maximum value is retained.The discarded product is then used as raw material for manufacturing new ones.Circular fashion promotes the reuse, repair, and restoration of products through fashion rentals; recycling; upcycling, and second-hand clothes purchases.Consumers appreciate recycling textile waste to produce new clothes and believe circular products should become "the new normal" [74].However, they need to be convinced that their behavior affects the environmental aspects of textile production.Both consumers and companies are morally responsible for creating circular fashion.However, consumers assume that businesses are for creating circular fashion as they created the fast fashion problem [75].Lack of suitable infrastructure and expertise, establishing reverse logistic schemes, consumer behavior, and communication of service propositions are some barriers to creating a circular fashion economy [76].
While incorporating circular business models, fashion brands face challenges, such as diverging perspectives of value, unclear success criteria, poor alignment with existing strategy, limited internal skills and competencies, and limited consumer interest [77].Solutions lie in emotion-based marketing, better business models, transparency in the exchange of information among the stakeholders, and better branding of SF [78].Some key drivers for consumers in engaging with fashion rentals are a sense of contributing to the cause of sustainability, efficient use of personal resources, and experimentation (in terms of styles and garments).The main concerns for fashion rentals are the considerations about the identity of the people to whom clothes are rented, the practicalities of service, and the aftercare of the items [79,80].Their existing engagement in second-hand purchases motivates them to become active players in a circular economy [81].
Swap shops and thrift shops are other emerging concepts that can bring in circular fashion.A few drivers for swapping are time efficiency, economical choice, convenience, sharing ethos, symbolism, anti-consumption, and frugality.Barriers to swapping can be a lack of accessibility and visibility, personal boundaries, quality concerns, lack of trust, etc. [82].For example, young mothers use social networks for exchanging children's clothing after being discouraged by limited acknowledgment of sustainable issues within the mass market fashion retail sector [83].The key predictors of thrift store shopping behavior can be classified into self-oriented attributes (the treasure hunting experience and seeking name-brand products) and others-oriented attributes (responsible citizenship).Among all the predictors, the treasure hunting experience has the highest predictive accuracy for high TSSB [84].Companies might strengthen their customers' rental or frugal purchase habits with organizational initiatives.For instance, raising consumer awareness of reuse and recycling, enhancing collection bin accessibility, increasing the collection of ragged or worn-out textiles and clothing, establishing a certification and accreditation program for charitable organizations, developing recycling technology, and creating durable and long-lasting designs are all possible strategies.

Theme 3: SF Consumption and Consumer Behavior (77 Papers)
Fashion consumption differs from any other product consumption, such as cosmetics or food, which have a direct impact on our bodies.Although fashion does not change a body's functionality, it affects the consumer's personality and the extended self.The consumers' SF purchase decision is influenced by their perception of the concerned brand, which claims to produce SF [85].Their general concern for environmental and social welfare, beliefs about SF, and their past behavior related to ethical consumption affect how they feel about SF fashion purchases [86].Additionally, trust and knowledge (about SF) positively influence the attitude toward SF and the intention to buy SF [87].Findings reveal that a consumer's inclination to be involved in SF consumption is influenced by self-enrichment and openness to experiencing personal values [88,89].Consumers concerned about animal welfare are more likely to purchase SF [89].Experts, such as retailers, marketing specialists, etc., confirm the spill-over effect, where a consumer of sustainable food also tends to consume SF [90].Consumers who are environmentally aware and habitually reutilize items, such as plastic, glass, and paper, tend to donate surplus apparel to charities [91].Those who prioritize style are more likely to recycle and reuse apparel [92].Self-concept has a positive influence on fashion lifestyle, which in turn, exerts a positive impact on purchase intention [93].Increasing one's self-expression and devotion to the environment improves the sustainable consumption behavior [94].Thus, consumer behavior in the context of SF is multifaceted and can be classified into sub-themes that have emerged from the literature.

Sub-Theme 1: Segmentation of Consumers (8 Papers)
Apparel consumers can be classified into four groups: concerned shoppers, holistic shoppers, traditionals, and apathetic shoppers [95].Sustainable apparel brands should develop strategies targeting the more committed consumer groups (i.e., concerned shopper and holistic shoppers), and can educate the other groups through appropriate communication.The consumers' attitudes and relevant social norms are the key driving factors for behavior changes [96,97].Based on attitude and driving motives, fashion customers can also be grouped into three categories: "Social consumers", driven by social image; "Self-consumers", driven by hedonistic wants; and "Sacrifice consumers", who can do anything to lessen their influence on the planet [86].Based on their emotional and shopping characteristics consumers can also be grouped as: "Distressed and Self-Oriented", "Warm and Thrifty", and "Cold and Frivolous" [98].Distressed and self-oriented consumers with maximum shopping characteristics are more likely to choose fast fashion.Warm and thrifty consumers with maximum emotional characteristics are more likely to choose SF.
Based on their motives, second-hand apparel shoppers can be classified into four categories: "Infrequent Fashionistas", driven by the fashionability motivation; "Fashionable Hedonists", driven by fashionability, as well as the surprising nature of an item; "Thrill-Seeking Treasure Hunters", driven by fashionability, and "Disengaged Second-Hand Shoppers", who seldom engage in this segment [99].Green trust, environmental attitude, and labeling satisfaction positively influence SF buying behavior [100].Six consumer typology groups with unique patterns of sustainable concerns can be found in SF: financially careless consumers, non-simplifiers, financially careful simplifiers, socially conscious financial simplifiers, sustainable, non-collaborative consumers, and sustainable consumers [101].Ironically, financially careless consumers show a reverse attitude-behavior gap in their green purchase behavior.SF brands can use these segments appropriately for better marketing and popularizing SF.Sub-Theme 2: Culture and Gender Influence (19 Papers) Age and gender are crucial factors affecting SF consumption.Older consumers are more involved in ethical consumption [88].Most papers have taken women respondents as the target population, arguing that women tend to purchase SF more than the other genders [29,30,75,[102][103][104]. They are also more likely to rent clothing online [80].Unlike men, women can buy clothes based only on ecological considerations.They place more emphasis on price-value considerations and do not want their sustainable attire to be obvious, whereas men imply the reverse [105].Women buy from thrift shops or reuse their clothes instead of buying new SF brands because SF is perceived as a high-end fashion with expensive costs [106].
There is a pronounced variation in how customers from other cultures view SF.In one study, participants from Canada portrayed an attractive and positive view of SF, while participants from France expressed concern about SF's "dullness" and lack of attraction.In the UK, the higher cost of SF was perceived negatively, whereas in France, it was perceived positively [29].Similarly, Chinese consumers have been found to be keener on SF purchases than Korean and Japanese consumers [107].The difference in behavior can be attributed to the cultural influences on perceived risks.Consumers' fashion orientation in a vertically individualistic culture (emphasizes hierarchy) is higher than those in a horizontally individualistic culture (emphasizes equality) [92].For example, US and UK consumers have more inclination to fashion than those from Sweden and Netherlands.The perceived efficacy of SF and prior knowledge of SF have a favorable impact on Indian customers' SF purchase behavior [108].Personal norms strongly influence the buying behavior of SF.Social conformity defines personal values regarding the SF consumption behavior of US Hispanics [109].Not just the buying choices but also the fashion avoidance choices are affected by culture and geography.Spanish consumers follow fast fashion avoidance, majorly influenced by a feeling of deindividuation and inauthenticity [110].Polish customers like SF only when the product meets their aesthetic, practical, and financial expectations [111].Promoting culture and expressions of creativity through education and innovative business models can lead to sustainable consumption.Stakeholders may induce a paradigm shift that can fulfill the fashion consumers' want for novelty and change without forgoing natural resources [112].
Sub-Theme 3: Young Consumers' SF Buying Behavior (7 Papers) Around 25% of the world's population is under the age of 15, and the world's median age is 31 [113].Thus, the world population is dominated by Generation Y (Gen Y) and generation Z (Gen Z) consumers.Gen Y refers to the Millennials born between the late eighties and mid-nineties, and Gen Z is the post-Millennials born between the mid-nineties and mid-2000s.As active fashion consumers, their actions and decisions affect the fashion trends.However, their attitudes/intentions do not necessarily translate into action, particularly when it comes to fashion products.Following the theory of consumption value, a higher conditional and epistemic value leads to a higher socially responsible purchase behavior [114].Young consumers' fashion disposition behavior includes donation, selling, repurposing, and swapping unwanted clothing.Factors, such as fashionability, the physical condition of an item, and social responsibility, have been reported to prompt their fashion disposition [115].They feel reluctant to dispose of fashion items with which they have formed an emotional attachment.
Gen Y consumers advocate for ethical fashion, while being skeptical of the information from companies about their products and believing that they are being subjected to greenwashing [30,115].Willingness to pay, environmental concern, and perceived value are significant predictors of the purchase intention of Gen Z for recycled clothing [116].For young adults driven by materialistic needs, a high level of success value is more likely to have a positive attitude toward SF purchases, and a high level of centrality value is more likely to hold a negative attitude toward SF purchases [117].Young consumers question the fast fashion phenomenon that confronts social values and traditions, especially in regard to using animal-based materials in fashionThey further admit that donating clothes is essential.Misalignment exists in the care and abstinence dimensions as young Indian consumers have a caring mindset but somewhat "mindless" behavioral orientations [118].

Sub-Theme 4: Anti-Consumption and Fast Fashion Avoidance Phenomena (3 Papers)
Anti-consumption opposes the speedy production and consumption of fast fashion.Consumer behavior can be conditioned with some negative beliefs associated with fast fashion.A few such beliefs include poor performance, overly trendy styles, big store discomfort, deindividuation, irresponsibility, foreignness, and inauthenticity, leading to the behavioral intention for fast fashion avoidance [103].Fast fashion customers often feel guilty about discarding costly, higher-quality goods that they have worn only a few times, and they end up donating them to charities.However, inexpensive clothing used for socializing soon becomes unsuitable due to wear and tear, and is thrown and later incinerated.SF promotes a minimalist closet or wardrobe (also known as a capsule wardrobe), having limited clothing that focuses on quality, longevity, and minimal or classic design.Consumers having capsule wardrobes report feeling less stressed, detached from fashion trends, finding joy in their fashion style, and an enhanced awareness of ethical consumption [119].Interestingly, every consumer has certain items in their closet/wardrobe that they neither wear nor discard.Many consumers wish to detach themselves from their wardrobes and discard the unwanted apparel, leading to great satisfaction with the contents of their wardrobes and less guilt about having unsustainable possessions [120].
Sub-Theme 5: Barriers and Motivating Factors for SF Purchase (15 Papers) Higher price is the most cited barrier to SF purchasing behavior [29,30,86,102,104,106,[121][122][123].There are other macro-environmental barriers, such as globalization, desire for economic growth, inadequate public policy, and lack of infrastructure and resources.A few micro-environmental barriers are the attitude-behavior gap, concerns about aesthetics, lack of knowledge and awareness about SF, perceived unreliability, and negative inferences about their functional performance [67].The motivation for fashion consumption from a customer's point of view can be based either on hedonic or utilitarian needs.Commonly cited hedonic motives include fun, satisfaction, the pursuit of bargains and materials not available in mainstream markets, a sense of uniqueness and individuality, satisfying the need for variety and change without feelings of guilt, and the opportunity to engage in environmentally friendly consumption of fashionable clothing.Utilitarian needs include prices, frugality, and smarter purchasing [76].The consumers who buy SF are partially driven by ethical obligation and mainly six values: self-expression, self-esteem, responsibility, protecting the planet, sense of accomplishment, and social justice.Product attributes such as unique styles, timeless cuts, quality, premium price, longevity, availability, natural materials, having been recycled, not produced in sweatshops, and being environmentally friendly production techniques are major influencers of SF purchase [102].
The fashion leaders are huge influencers in the process of acceptance and purchase of SF.Factors such as fashion consciousness, fashion knowledge, confidence in decisionmaking, and mood enhancement are a few of the most important psychological factors influencing male fashion leadership behavior [123].Male fashion leaders use colleagues and friends as the primary information sources for fashion.The clothes/apparel attractiveness, brand name, store image, and quality positively influence the male fashion leadership, while value for money negatively affects it.
The lack of information provided by the fashion industry has led to the consumers' resistance to the relevance of sustainability in fashion.There is a limited understanding of fashion production and why this compromises sustainability, mainly because there are no stimuli within the retail environment to revive the consciousness of the issues [104].Past environmental behavior, peer influence, and SF knowledge influence SF perceived benefits and, consequently, SF purchase behavior.Perceived benefits can be related to perceived value in buying fair trade clothing and self-image enhancement [124].Table 1 shows few of the barriers to SF listed in the existing papers.Lack of visibility/accessibility to consumers [121] Sub-Theme 6: Attitude-Behavior Gap (11 Papers) Even though consumers show a favorable attitude towards green consumerism and environmental consciousness, the relationship between attitude and purchase behavior is not necessarily positive.It is affected by personal circumstances and other hindering factors such as price, lack of availability, transparency, image, lack of information, inertia, and consumption habits [125].The probable reason behind the attitude-behavior gap can be the insignificant relationship between green trust and environmental attitude and concern [100].Fashion consumers express concern about fashion sustainability issues but are unwilling to engage in SF consumption due to traditionally negative perceptions of SF [126].The main impeding factor apart from the price is the lack of information.Their knowledge and behavior towards SF remain similarly ambiguous for insufficient information to determine what pertains to sustainable behavior or what aspects of production lead to unsustainability [127].Consumers seldom question their choice of eco-apparel, unlike organic food or cosmetics.This is because how they are dressed has no real impact on their bodies.For instance, consumers frequently check the fair trade tags on fruits before purchasing, but these terms are less well-defined or understood when applied to clothing [63].
Consumers identify luxury and sustainability as contradictory.They have a consumptive dilemma in choosing between basic clothing needs and unnecessary materiality.While making the purchase decision, consumers also think of others in need.As per Buddhist economics, ethical clothing consumption relates to seeking sufficiency in one's clothing needs and gratefully using clothing to serve one's true potential rather than the ego [128].The value behind sustainable luxury consumption can be categorized as self-oriented (personal) value and others-oriented (social) value.Self-oriented values include hedonic and universalistic virtues, whereas others-oriented values include power, achievement, security, conformity, tradition, and benevolence [129,130].Any of these values can take precedence while making a purchase decision for SF.Social capital is reported to positively influence SF's purchase intention when fashion influencers promote SF in their YouTube videos [131].In fashion, aesthetic value takes precedence, unlike other vegan products, such as food.Consumers do not shy away from buying products made entirely from animal fur.Globally, consumers are unwilling to sacrifice their need for appearance and flashiness in favor of an individual prosocial status [132].However, consumers who are more empowered, more confident, and capable of exercising control over their lives are willing to consuming clothes consciously [133].
Sub-Theme 7: Adoption of SF (5 Papers) Social acceptance and the threat of exclusion majorly prompt the adoption of sustainable offerings.However, the adoption patterns are skewed and do not show a continuous trend [121,122].Staged experiences can endorse consumer learning about SF consumption.They inspire consumers to grow their modified criteria for distinguishing between different SF alternatives and increasing the chances of SF adoption [126].Various theories have been proposed to explain the adoption pattern of SF, such as the trickle-down, trickle-up, and trickle-across theories.An improved approach combining all three of these theories, i.e., the triple-trickle theory, can be used to understand the pattern of SF adoption [134].Ideally, trickle-up and care for the environment and people are the first steps in the process.Millennials are disseminating this information through social media, which fuels fashion trends.The news, social media, and the internet are preferred sources for initiating an SF trend.The number of users sharing content and conversing on social media raises awareness of SF.When consumers on a larger social scale choose SF brands, the SF trend spreads [134].The genuineness of SF, concern for the adverse impacts of the fashion industry, supporting local businesses and workers, etc., and feeling good about contributing to a better world are a few other drivers for SF adoption [106]  For fashion to be sustainable, it has to be sustainable throughout its lifecycle, from design to disposal.Achieving this involves a considerable share of B2B processes and their sustainability.Fast inventory turnover, mass production, and short lead times are characteristics of fast fashion, which boost productivity and profits.As a result, it is simpler for fashion manufacturers to adapt to fast fashion than SF [110].Sustainable fashion product manufacturing requires a sustainable product and technology purchase.This aspect has not received adequate attention from researchers.Given the multi-disciplinary nature of such topics, it is also possible that relevant papers have not found a place in traditional marketing journals.A macro-marketing perspective using a network approach involving different stakeholders is necessary to make consumption more sustainable and find long-term solutions [135].
Sub-Theme 1: SF Supply Chain (8 Papers) The primary issue in the fashion industry supply chain is that the scale and scope of the current approaches to sustainability are limited and fail to address more fundamental challenges linked to the dominant business models and consumption behaviors [136].There has been less research on how the stakeholders in the textile industry optimize their sustainable operations or involve the suppliers in sustainable operations [121].SF marketing can be revolutionary given proper value calculation, which integrates business, society, and the environment.There is a need to refocus marketing emphasis on want satisfaction instead of acquiring goods, operationalizing SF marketing, and enhancing value creation [137].Transparent business models and an effective evaluation system positively affect environmental concerns, brand trust, and willingness to enact environmentally conscious behavior.Sustainable knowledge moderates the effects of business transparency on environmental concerns and brand trust [138].Businesses treating sustainability as a corporate goal can bring a large shift in the supply chain, which could pay dividends in raising their business profile and building customer loyalty [139].Reducing the material flow in the fashion supply chain can be hugely impacted by clothes-swapping, where consumers can change "roles" (as supplier and consumer) multiple times as they go through the consumption cycle.This fluidity of consumers being consumers and suppliers simultaneously is a vital characteristic of these swap shops and provides a unique opportunity for disruptive business models [106].Key aspects of sustainable supply include: going beyond monitoring, adopting a comprehensive approach, looking beyond the first tier of suppliers, integrating sustainability into core business practices, and bringing transparency to the supply chain [140].A robust market system also has to be in place.Achieving this requires the involvement of all stakeholders (i.e., consumers, government, business houses, fashion associations, organizations, designers, etc.) working towards a more sustainable fashion system [141].Stakeholder capitalism and a transparent value chain have to be incorporated to benefit the customers, suppliers, employees, shareholders, and local communities.It will address all three pillars of sustainability: environmental, social, and economic.4.2.5.Theme 5: SF Retail.(6 Papers) Retailers can positively influence and drive consumer demand for SF.In the extant literature on SF retailing, five key areas are covered: sustainable retailing in disposable, fast, and slow fashion; green branding and eco-labeling, retailing secondhand fashion; reverse logistics; and e-commerce opportunities [142].Most studies target Western developed markets, whereas issues persist primarily in developing markets.SF retailing in the brickand-mortar form is more trusted by consumers than e-retailers.E-retailers can improve their business model with a web presence, information competence, value integration, and creative market development.Enhanced business integration, learning, and knowledge can maximize business value [143].Making clothes durable or promoting longevity can address the motives of anti-consumption.However, this is obstructed by the traditional supply chain and retail structures, which restrict the stakeholders, particularly suppliers, from fully utilizing their skills and knowledge within operational multi-disciplinary teams [144].Thus, designing long-lasting clothes faces a conflict between commercial drivers and sustainability imperatives.The management of fashion retail based on reuse is complex and is hindered by the differences in prioritization, knowledge, experience, skills, coordination, and material conditions [145].Consumers' expectations from fashion retailers are associated with three factors: responsible citizenship, treasure hunting, and looking for name brands.Thus, thrift retailers must re-position themselves as "sustainable fashion shopping destination" to satisfy the customers' expectations [92].Short-term temporary retail stores or pop-up retail are gaining popularity worldwide, especially in the fashion field, wherein the stores are open for a short while for a flash sale.These stores can be considered valuable marketing tools in SF for various strategic purposes, such as brand community and tribal marketing strategy, brand experience, and market research [146].

Discussion
Fashion promotes continuous change and consumption, which is problematic in achieving sustainability, net zero, and the SDGs.Sustainable fashion aims to address this by making fashion products more socially and environmentally responsible.The innovative marketing of sustainable fashion can ensure that more people consume SF.This paper aims to map the existing literature to understand the various issues related to the marketing of SF and answer two research questions.

•
What do we know about marketing sustainable fashion (SF)?

•
How can marketing facilitate the popularization and mainstreaming of SF?
Over the last three decades, SF research has made considerable progress, evident from the number of papers published in leading journals.Five key research themes (see Figure 9) emerge: marketing communication and branding, product specifications, consumer behavior, organizational purchase, and SF retail.Many papers discuss how pro-social or pro-environmental consumers are also likely to be pro-SF.Young female consumers are likely patrons of SF, provided there is authentic and credible communication about the sustainability aspects of SF products.Fashion retailers play a significant role in mainstreaming SF by positively influencing consumer behavior.Increasing consumption of SF instead of traditional fashion or fast fashion products would be the key to achieving the Sustainable Development Goals.Thus, (addressing our second research question) mainstreaming SF will require more concerted and innovative efforts from fashion brands.Drawing on the findings of this review, boosting the demand for SF will require brands to focus on improving communication and managing pricing.They need to move away from greenwashing and engage in authentic conversations on SF, particularly to those target groups that are already sensitive to broader sustainability issues, such as the environment, care for animals or social equity.However, it is not clear if the barrier of high price can be tackled only through communication.A large part of the developing world, which is also the growing market for the fashion industry, has low income consumers who are price-sensitive.The current macro-environmental uncertainty, increasing cost-of-living, and geo-political tensions make the adoption of high-priced SF even more difficult.A solution may lie in circular business models, as well as sustainable and frugal innovations in raw materials, products, and processes.For example, leading brands, such as Kering and Arvind, are collaborating on alternative cotton farming [147] methods that are more sustainable.We need to understand the organizational uptake of such new technologies and their impact on brand revenue.

Theoretical Contribution and Future Research Directions
Firstly, this paper adds to the existing body of research on the marketing of SF by mapping the literature and identifying key themes covered till 2021.Second, this literature review identifies potential research gaps for future research directives.While several theories, such as the theory of planned behavior or reasoned action, are widely used [96,97,110,114,134], SF research will require more transdisciplinary research drawing from sociology, history, public policy, human geography, happiness studies, and partnership studies, to name a few.For example, how have policies related to extended producer responsibility (where corporations become responsible for the waste created by their products) influenced fast fashion companies to adopt their product and marketing strategies?How do industry-led collaboration platforms, such as the Sustainable Fashion Coalition, impact SF promotion and consumption?This work will help propose newer theory formulations in the SF research area.
In our review, 77 out of 97 papers are based on consumer behavior related to SF.This is expected, as consumer demand drives the market, it is easier to collect consumer-level data, and it is more convenient to influence consumer behavior with marketing efforts.However, the aspect of organizational buying (supply chain) in SF must also be sustainable to achieve an end-to-end sustainable fashion value chain.Our review suggests scope for further work in organizational purchases and B2B marketing in SF.Future studies should focus on business marketing planning, theories, and strategies for mainstreaming SF.
Based on the discussion above, we provide a few possible areas for future research: B2B marketing in SF: Much of the existing SF marketing research is focused on the demand side-factors and barriers to consumers' consumption behavior or acceptance/adoption of SF.On the other hand, not much is known about how SF brands can create a compelling value proposition using alternative materials (to cotton, for example) or processes (such as the waterless dyeing of T-shirts and usage of regenerative agriculture to produce sustainable fabric).Research on industrial marketing initiatives is required to understand how more companies can adopt such solutions and at what cost to the producers and consumers.For example, how do companies create collaboration with suppliers of green technology and processes, and how that influences product forms and function?How do suppliers of sustainable raw materials, such as organic cotton/green chemical-based dye/low water technology providers, market to large B2C apparel brands?It is also interesting to see if and how large B2C brands acquire new sustainable raw material suppliers and what it means for buyer-seller relationships.Case-study-based research on B2B marketing practices in different SF brands can be a starting point.Research objectives may cover questions such as how existing SF brands engage with their suppliers to procure sustainable technologies and eco-friendly raw materials, develop or adhere to sustainability standards throughout the production-to-sale process, and what business marketing strategies they follow.It will eventually have implications in practice.
Business model innovation: The circular economy provides an opportunity for reusing fashion products.Future research can look at the institutional dynamics of such business models, e.g., how fashion brands create a global reverse logistics system without impacting brand image.Promotion of sharing and rental in fashion will also lead to better sustainability performance.Adopting pre-used clothing across different social groups in emerging markets could be another potential study area.This has implications for international marketing and non-profit sector marketing, as much of the used clothing in the West is donated to charities/charity shops, which in turn is sent to African countries for re-selling in local markets.Many reports suggest that the poor quality of fast fashion products makes them unsuitable for reselling, and importers often end up incinerating such clothing.
Another possible area to explore would be the direct-to-consumer (D2C) model, where companies sell directly to consumers without any intermediaries.Reduced intermediaries lead to cheaper products and quicker deliveries/returns.D2C e-commerce sales in the US surpassed USD 128 billion in 2021 and are forecasted to grow to almost USD 213 by 2023 [148].Using digital and influencer marketing can be effective in mainstreaming SF.There is further research potential regarding barriers, antecedents, and future trends of D2C SF brands.
SF Pricing: More studies are required to understand how consumer price-sensitivity can be managed.This assumes significance on two fronts.First, a major market for SF lies in the developing world, where resource-constrained customers have a high pricesensitivity.Second, the conventional response to price may not hold true in the case of circular fashion.For example, it would be essential to know the pricing behavior towards SF when consumers rent or swap clothing.While it has been established that price is a barrier to SF purchase, it is not known what premium consumers are willing to pay for SF, if at all, in both developed and developing markets.With a cost-of-living crisis in Europe, many consumers are expected to turn to charity shops for their clothing supplies.SF pricing in such outlets could generate relevant theories for wider SF adoption.SF in emerging markets: Most of the existing research has been performed in developed economies whose social, cultural, and political settings differ from other nations' [29,30,75,[102][103][104]. The claims from the existing research cannot necessarily be generalized for developing or under-developed nations.More studies are needed in the context of developing countries, keeping their socio-political, cultural, and economic dynamics in consideration.For instance, as per Buddhist economics, SF consumption is related to the feeling of serving others [128], and this could have implications for countries such as Thailand, Vietnam, and Sri Lanka.Thus, with different religious and cultural practices, the developing or under-developed nations may have varied theories of SF consumption.The sharper rural-urban divide and income inequality in many such countries imply that existing research findings are unlikely to hold true for rural consumers in markets such as Brazil, Indonesia, South Africa, and India, and new theories are needed.
Brand recall and marketing mix: Consumers form a brand identity based on their message communication, gradually leading to their purchase intentions [59].The extant literature also supports the claim that SF is not adequately branded.On the other hand, many fast fashion brands resort to opportunistic greenwashing and create sustainable brand extensions to gain a sustainable fashion image.In contrast, SF brands lack such brand recall.Future research can focus on key green language terminology for the efficient branding of SF [65].
Mainstreaming SF: SF remains a niche product category that is yet to be mainstreamed.Mainstreaming in this context is transforming from an explicit or niche group to a common population, from marginalized to empowered, and from excluded groups to included groups [149].For mainstreaming SF, there needs to be wide acceptance and adoption of the values promoted by SF-sustainability, longevity, and quality.Both pragmatic and radical research should collaborate to translate SF into mainstream practice [79].The research areas indicated above can contribute to SF mainstreaming.There are still significant gaps in knowledge, particularly in understanding SF habit formation in individual consumers and companies [121].This will require a transformation of the fashion value chain.SF needs to be both affordable and desirable.Fashion for the poor needs researcher attention for mainstreaming SF.
Managerial contribution: Our primary research objective was to find the state-of-theart in SF marketing research and explore ways to mainstream SF through marketing.This has crucial suggestions for managerial implementation.Our review identified that price is the primary barrier to SF purchase behavior, supporting the findings from several papers reviewed [29,30,86,102,104,106,[121][122][123].Lack of information is the second most crucial barrier to SF purchase behavior.Despite the barriers, there are several opportunities for SF marketers.The SF market is growing at 9% and is expected to have a revenue of USD 8.3 billion in 2023 [150].Our analysis reveals that value proposition and business model innovation for SF are potential areas for future work.
Our work provides inputs for the manufacturers, governing bodies, consumers, policymakers, and other stakeholders involved in the value chain of the SF.Based on our analysis, we recommend the following:

•
Marketers and brand managers have to take up strategies for creating awareness and education of consumers regarding the SF and the peripheral activities related to its value chain (from eco-friendly raw material procurement to environmentally safe disposal or recycling).For example, consumers' knowledge about eco-labels can be enhanced through marketing;

•
The SF brands should work towards making value-based segmentation [10,98,99,101] and pricing strategies.For example, customers value fast fashion companies' lowpriced trendy designs.Similarly, SF brands must create a value proposition for customers in terms of longevity, sustainability, and social responsibility;

•
Findings indicate a need for macro-marketing and policy-level change for mainstreaming SF [135].Macro-level changes, such as policy formulation, certification on authenticity, or keeping a tab on sustainability across the fashion value chain, measures for fair trade, etc., can bring long-term change in the SF value chain.There is a need for national and global collaboration among leading brands to establish national/global frameworks for sustainable fashion.Initiatives such as the sustainable fashion coalition [151] can help SF brands to collaborate and co-create marketing strategies to mainstream SF; • Our findings suggest that social media platforms are the most effective way for consumers' to engage with SF.Thus, marketers and managers should leverage social media's effectiveness innovatively through digital and influencer marketing.Marketing communication will be able to create narratives that promote values aligned with SF;

•
Retailers can play an essential role by choice editing-deciding what to keep in the store to influence consumer choice and purchase.They can also design a reverse logistics system and encourage customers to return clothes to designated points, thus promoting a circular transition in SF.
The main goal of the UN fashion charter [152] is to drive the fashion industry to netzero emissions no later than 2050.More than 130 companies (including brands, retailers, and suppliers) have joined the Charter taking accountability for reducing emissions and minimizing their adverse effects on climate.Innovative marketing can help them achieve this worthy goal.

Conclusions
Fashion consumption reflects the human need for self-expression.It also adds significantly to greenhouse gas emissions and accelerates climate change.Sustainable fashion products can limit the negative impact of fashion, and marketing can help to make SF more popular.This paper systematically reviews the literature on past trends and future directions for marketing SF.Ninety-seven papers published in ABDC-listed marketing journals were selected using structured inclusion and exclusion criteria.Most papers focus on consumer aspects of SF-barriers, motivation, and adoption to name a few.Five key themes emerge from the systematic review-marketing communication, branding, product specifications, consumption, consumer behavior, organizational purchases, and retailing.Several areas of future research emerge-the role of organizational buying in bringing down SF prices, new business models, such as circular fashion, need for extensive and exhaustive marketing communication, emerging market issues and challenges, and industry collaboration for mainstreaming SF.
There are certain limitations to our study.The papers selected in this review are from ABDC-listed marketing journals, with minor exceptions.With a search using particular keywords in certain databases, a few related papers might have been missed.While fashion supply chains have been charged with social irresponsibility regarding human rights violations, they do not find a prominent place in marketing journals selected for this paper.Several technical aspects of fashion design and communication find a place in technical journals that were out of our search.Future research may refer to other databases, such as Springer and MDPI, which will result in additional literature in this field.Finally, fashion is a broad area of study covering diverse industries, such as jewelry, cosmetics, luggage, and apparel.We have considered only the textile/apparel/clothing industry for this review.Taking up fashion products apart from apparel can be interesting for future research.
One aspect of fashion is the newness and novelty it brings to one's life.The other aspect contributes to global warming and climate change.The world is combating ecological issues, such as water scarcity, depleting green cover, glacier meltdown, and many climaterelated phenomena.Questionable supply chain practices also hamper social dynamics.It is time for action, and SF, thus, is not an option but a need.It provides ways to make fashion more responsible, and effective marketing of SF can ameliorate much of the harm caused by the industry, even as questions remain about what to do with conspicuous consumption.This paper contributes to the existing academic work with probable areas for further work,

Figure 1 .
Figure 1.Key steps of the methodology.

Figure 1 .
Figure 1.Key steps of the methodology.

Sustainability 2023 , 29 Figure 3 .
Figure 3. N X N matrix with areas covered in literature and factors affecting them.Figure 3. N X N matrix with areas covered in literature and factors affecting them.

Figure 3 .
Figure 3. N X N matrix with areas covered in literature and factors affecting them.Figure 3. N X N matrix with areas covered in literature and factors affecting them.

Figure 4 .
Figure 4. Classification of articles based on their research approach.

Figure 5 .
Figure 5. Years of publication with the respective number of publications.

Figure 4 .
Figure 4. Classification of articles based on their research approach.

Figure 4 .
Figure 4. Classification of articles based on their research approach.

Figure 5 .
Figure 5. Years of publication with the respective number of publications.

Figure 5 .
Figure 5. Years of publication with the respective number of publications.

Figure 6 .
Figure 6.Paper distribution among the selected journals.

Figure 6 .
Figure 6.Paper distribution among the selected journals.

Figure 7 .
Figure 7. Distribution of publications worldwide.The selected papers have followed quantitative, qualitative, and mixed (quantitative and qualitative) methodologies.Figure8illustrates the research methodologies and approaches followed by the papers.Qualitative research methods (used in 40 papers) are most preferred.

Figure 8 .
Figure 8. Research method and approach followed in the selected papers.
illustrates the research methodologies and approaches followed by the papers.Qualitative research methods (used in 40 papers) are most preferred.Sustainability 2023, 15, x FOR PEER REVIEW 10

Figure 8 .
Figure8.Research method and approach followed in the selected papers.

Figure 8 .
Figure8.Research method and approach followed in the selected papers.

Figure 9 .
Figure 9. Classification of major themes and sub-themes emerging from the analysis.

Table 1 .
Barriers to SF as per extant literature.