1. Introduction
Plastic pollution is increasingly gaining attention from researchers and policymakers at the international level since it is a public good with a global dimension [
1,
2,
3,
4,
5,
6]. In particular, the use of single-use plastic bags has been identified by many scholars as one of the major sources of plastic pollution, especially those with inherent chemical properties which make them non-biodegradable [
4,
7]. In addition to this undesirable attribute, other characteristics such as cheapness, convenience and availability make single-use plastic bags more likely to be pushed by retailers at the expense of durable alternatives on the market [
8]. While the ecosystem lacks the ability to sequester such type of waste material generated by economic activities, the consumption of non-biodegradable plastics imposes an externality on society by compromising environmental aesthetics or beauty which translate into reduced market value to real estate properties [
9], posing harm to both terrestrial and marine wildlife [
10], and blocking the drainage system in cities, thereby exacerbating the incidences of diseases and floods [
11]. Although the evidence is still scarce, microplastics are also believed to cause health problems in human beings [
12].
Globally, seventy million tons of plastics are generated annually from economic activities associated with the production, distribution, and consumption of household goods [
6]. Thousands of people depend on the plastic industry as a source of livelihood across the globe being employed in either a formal or informal plastic value chain [
3,
9]. Evidence reveals that plastic consumption is on the rise, especially in developing countries due to rapid urbanization caused by high population growth rates, rural–urban migration and rising household incomes resulting from long working hours and increased participation of women in the labour force [
13]. Projections show that the population in developing countries is expected to double by 2050 being attributed to growth in the share of informal settlements or urban slums [
3], which in turn might translate into increased plastic consumption in the absence of appropriate measures [
14].
As a matter of concern, plastic pollution is increasing despite efforts by policymakers to reduce consumption through policy interventions ranging from simple behavioural interventions such as information provisioning or awareness campaigns [
3] to market-based instruments such as plastic levies [
2]. This situation culminated in most governments across the globe (including a few leaders in developing countries in Africa such as Kenya, Uganda, and Rwanda) implementing hush policies in the form of a ban on single-use plastic packaging [
15]. Such a policy is often difficult to justify given the contribution of the plastic sector to the whole economy and the fear that the majority of households depending on the plastic industry for survival will end up losing their jobs [
13,
16]. As a result, this policy has been highly contested in Southern African countries such as South Africa and Zimbabwe [
15,
17].
Policy instruments in developing countries are fervently endorsed based on weak empirical evidence and as a result, such policies fail to achieve the desired outcomes [
17]. For instance, little is known about consumer preferences for attributes of shopping bags such as the convenience of use or disposal, recyclable, reusable, durability, and style. Important stakeholders such as consumers affected by a government policy are not usually consulted during policy designs and studies of this nature allow actor or beneficiaries to communicate their needs and wants [
18]. Based on a review of empirical literature from developing countries, ref. [
8] observed some gaps with regard to information about why and how consumers choose among the different types of shopping bags, be they plastic (single-use plastic bags versus recyclable), paper or cloth. This important information is part of the building blocks in understanding consumer behaviour and can help policymakers to craft better policies aimed at addressing plastic pollution. Furthermore, most of the previous studies were either qualitative in nature or employed descriptive statistics (e.g., [
9,
16,
19,
20,
21], while few studies employed rigorous econometric techniques to provide objective evidence relevant for policymaking [
22,
23]. As a result, most of the policies used in African countries to curb plastic consumption were adopted from first world countries with little or no effort made to adapt the instruments to suit local conditions.
Given the background above, three important policy questions arise: (i) Which attributes matter for purchase decisions involving alternative shopping bags available on the market in Cape Town? (ii) Does the choice of shopping bags and their attributes tell us something about sustainable behaviour? (iii) How can policy facilitate the adoption of sustainable behaviour by influencing consumer choice among the alternative options? This study uses a choice experiment to elicit consumer preference for attributes of shopping bags in the context of an African city such as Cape Town where plastic consumption is increasingly being exacerbated by rapid urbanization coupled with a high population growth rate. By so doing, our study provides pragmatic evidence to policymakers and insights into consumer tastes and preferences for alternative packaging that is available on the market. While consumers are usually able to communicate their tastes and preferences for most products within budget through actual purchase, preference for some products outside the consumer’s reach remains largely unobservable. An understanding of the attributes that influence the consumer’s decision to buy or choose a particular type of shopping bag over another is required to craft better policy interventions to incentivize sustainable behaviour so that potential demand for alternative options that are ordinarily not considered in the consumer’s shopping basket for some reason can be translated into effective demand in the future. Our study also contributes to the literature addressing plastic pollution through modelling consumer preferences which indirectly speaks to the adoption of sustainable behaviour either by reducing the consumption of single-use plastic bags or increasing the demand for durable multi-use packaging. We also contribute to the literature on the methodological front.
The rest of the paper is organized as follows.
Section 2 presents the design of the choice experiment paying particular attention to the procedure used in its design, including a detailed description of the attributes, while
Section 3 describes the case study.
Section 4 focuses on the research methods, theoretical underpinnings of the model, sampling and data. The results and discussion of this study are presented in
Section 5 and
Section 6, respectively. Finally, we conclude and provided the policy recommendations in
Section 7.
3. Case Study Area
Cape Town is a multiracial society with consumers from diverse backgrounds and a culture that spans across different countries and continents [
42].
Figure 1 shows the map of the city of Cape Town. According to the results of the most recent census conducted by Statistics South Africa [
43], the majority of the population are coloureds (42.4%), followed by black Africans (38.6%), white Africans (15.7%%), and finally a small proportion of Asian or Indian communities (1.4%) and others (1.9%). Past evidence reveals that the coloured population has been falling over time, while the black population increased [
44]. For example, the 2011 census found that the share of coloured people in the Western Cape fell from 54% in 2001 to 49.6% in 2011 while the white population dropped from 18.4% to 16%. The black population increased from 26.7% to 33.4% while the Indian population grew slightly to 1.1%. Growth in the black African population is caused by rural–urban migration and foreigners coming in from other African countries [
43].
The economy of the city is based on tourism and wine farming which is also complemented by a vibrant retail industry of supermarkets and restaurants [
45]. Most supermarkets combine both grocery and fast food sections to cater for the ever-growing market. An increase in the number of women recruited in the job market coupled with an increase in the number of consumers who prefer to eat fast foods signalled an increase in the demand for consumer goods and services and growth in the retail sector [
46].
While Cape Town is not an exception, economic growth and urbanisation have contributed significantly to environmental pollution and the degradation of ecosystems in South African cities as firms and households seek to maximize their objectives. Like most cities in South Africa, the city of Cape Town has also experienced significant growth in informal settlements, which has also contributed to waste generation in the informal sector [
47]. The occurrence of the informal sector, poverty and inequality contributes to the complexity of implementing the green city philosophy in Africa. Even though the informal sector contributes a fair share of environmental pollution, it is difficult to instil discipline and sustainable behaviour in poor communities due to lawlessness and lack of infrastructure. Policymakers face a trade-off in terms of choices between policies that favour environmental sustainability and rehabilitation and policies that contribute to poverty reduction [
2].
The retail business sector generates a significant amount of solid waste (e.g., plastics, glass, paper, cardboard) and organic waste (e.g., vegetables, meat, cooking oil and grey water). Most of the waste will eventually end up in landfill, on the streets, blocking drainage systems or polluting the oceans, while a small proportion is recycled or reused [
48]. There is a call for the retail business sector to adopt sustainable behaviour to reduce the amount of pollution generated. Different strategies are available, and these include waste minimization or reduction, reuse, recycling, and recovery.
6. Discussion
Our sampled respondents are consistent with young, educated, and working-class respondents with access to the internet. In present-day society, these are either the decision makers or breadwinners in poor and medium-income households in most developing countries [
42]. It is also not surprising that most of the respondents who either participated in FGDs or reacted to this survey are interested in environmental issues given that plastic pollution is increasingly becoming an issue in many societies and most jobs address this issue. Previous studies also indicated a very high level of awareness of plastic pollution in African cities [
1,
20]. As a result, there might be self-section bias which we could not solve in this study since most of the respondents who responded to this survey either work in the environment sector or have some sort of environmental education background from school and are aware of plastic pollution. In designing our choice experiment, we made sure to avoid linking plastic bags with environmental pollution at the beginning which could bias our results. The choice experiment was administered first before respondents were asked about their awareness of plastic pollution. As a result, the decision that respondents made during the survey is similar to a real-life scenario they face at the point of purchase. Because of this, we do not believe that our results would differ if another random sample of respondents which includes those without access to the internet was drawn.
Evidence shows that both low- and medium-income households are the biggest consumers of single-use plastic bags, partly because they are very cheap and partly because of a lack of awareness of either the magnitude of the problem of plastic pollution in their area or its consequences [
4,
9]). The latter is a stylized fact in the literature which has not been subjected to rigorous econometric testing in developing countries [
8]. Our survey results show high awareness levels of plastic pollution in Cape Town across different population sub-groups. This result is also corroborated by qualitative information gathered through FGDs and key informant interviews. Given a very high level of awareness of plastic pollution, most respondents indicated a preference for alternative shopping bags which is also consistent with previous studies [
23,
30]. Although most of these studies are from first-world countries, there is increasing awareness of plastic pollution and a need to change to alternative packaging [
9]. Most of the respondents in this study indicate a preference for shopping bags made of cloth because they are durable, attractive, and reusable. Why then does rhetoric deviate from the actual behaviour of the respondent? According to survey results, key informant interviews and FGDs, the answer to this question might be associated with the cost of alternative shopping bags which act as a deterrent to most customers.
The maximum that respondents are WTP for single-use plastic bags (choke price) is several times higher than the current price that respondents are facing on the market, while the minimum they are WTP for alternative packaging, which we refer to as the price floor in our analysis, is way below the market price. On one hand, our results confirm another stylized fact from previous studies that the plastic levy could be suboptimal [
5]. On the other hand, our results speak to the use of market-based policy instruments aiming to reduce the utilization of single-use plastic bags either through an increased plastic levy or increased consumption of multiuse packaging via a subsidy. This means that increasing the levy could act as a disincentive for single-use plastic bags while a subsidy acts as an incentive to increase the consumption of alternative shopping packaging [
67]. An optimal outcome might be achieved if these two policy instruments are used in combination rather than in isolation [
8]. However, it is also important to note that the benefits of combining these two policy instruments might not necessarily exceed the benefits of using either a levy or subsidy in isolation [
18]. A system where the joint effect of two or more interventions is dissipated is inefficient and is costly to society. The conditions under which this happens are not known with certainty since this depends on the context and might be subject to empirical investigation.
It is not surprising that the status quo bias is insignificant given that most respondents are aware of plastic pollution. Consistent with previous studies, our results show that the drive to reduce plastic pollution is present in all communities under consideration whether we consider low-, medium- or high-income areas. Consistent with previous studies, the results of this study demonstrate unhappiness with deteriorating environmental conditions as a result of plastic pollution [
1,
20]. According to FGDs and key informant interviews, residents in low-income areas identified plastic pollution as one of the main causes of blockages of the sewage and drainage system and flooding as its impacts. Evidence shows a reduced value of properties located near dumpsites and informal settlements where the challenge is most pronounced [
68].
Consistent with what is happening on the ground, preference for small-sized shopping bags is associated with convenience in use and disposal [
32]. The problem is that when customers make a purchase decision, they do not take into consideration convenience in use and the externality that is imposed on society when the shopping bag is final dispose-off [
50]. It is debatable whether consumers make a joint decision about consumption and pollution at the point of purchase when they buy plastic bags given information constraints, particularly in developing countries. Given that customers are aware of the problem of plastic pollution, the type of information conveyed becomes imperative from a policy point of view to incentivize a reduction in plastic consumption [
1]. The common narrative is that plastic pollution is associated with poor households or communities simply because plastic litter is dumped on the street, yet a huge amount of litter is channelled through the formal system which ends up in dump sites or the ocean [
69]. Such contribution to plastic pollution is often neglected since it is unobservable or nonattributable to a single community. Therefore, rather than conveying the usual message about pollution, an awareness campaign could be tailored to suit the needs of different market segments.
Our results demonstrate a preference for both small- and medium-sized shopping bags relative to the status quo since they are more convenient for most users. Small- and medium-sized packaging do not only allow shoppers to disaggregate goods into small units but also according to other measures of convenience such as the danger posed by combing food stuff and chemicals [
33]. FGDs revealed that most shoppers prefer to use small and medium-sized shopping bags together for more convenience. In this sense, small and medium-sized shopping bags actually act as complementary tools rather than substituting each other. Therefore, large shopping bags are less preferred since they do not offer these attributes. Furthermore, the use of different sizes of shopping bags makes it possible for customers without transport to strike a balance between short and long-distance travel on foot [
9].
The fact that small-sized shopping bags are more preferable compared to the status quo in low-income areas confirms that poor households are more concerned with convenience in use since they carry the goods long distances, while medium-sized shopping bags are more preferred relative to the status quo in medium- and high-income areas since they have transport [
1]. Small-sized shopping bags are less preferred compared to the status quo in high-income areas perhaps because the respondents are aware of plastic pollution or they own transport and hence need to save costs. Reusable shopping bags are preferred compared to the status quo across income areas. This is interesting because the motives could be different. For example, poor households are aiming to save costs, while nonpoor households are concerned about the environment [
9,
23]. Large-sized shopping bags are less preferred relative to the status quo in low- and medium-income areas since convenience is compromised, especially if the shopper travels long distances [
70]. Large-sized shopping bags makes shopping bags heavy and difficult to handle [
1]. Consistent with the literature, a preference for more durable shopping bags in medium and high-income areas could be associated with environmental concerns [
70]. It is not surprising that styled and branded shopping bags are preferred in high-income areas since evidence reveals that relatively wealthy customers respond to such marketing strategies as income increases [
9].
Our results show that the highest WTP is associated with the medium-sized shopping bag confirming that customers prefer averages to extremes as suggested in microeconomic theory [
71,
72]. The second highest WTP is associated with reusable shopping bags, followed by styled shopping bags. According to FGDs, the least preferred or lowest WTP is associated with large-sized shopping bags since carrying the goods becomes heavy and difficult, especially if the customer does not have transport. Surprisingly, the WTP for recyclable shopping bags is also low even though this attribute is ranked high by respondents.
From a policy perspective, we are interested in the convergence between the WTP and the maximum price that respondents are willing to pay for a single-use plastic bag (choke price) or the minimum price for alternative durable shopping bags (price floor). From the characteristics of goods theory, respondents are able to disaggregate the price of a product according to its attribute and then aggregate the individual prices again to arrive at the price of a whole. By aggregation, we arrive at the following conclusions and prices of different types of shopping bags. The WTP of a small shopping bag that is recyclable is R2.99 which approaches the choke price for a single-use plastic bag of R2.92. Therefore, the optimal price of a recyclable is around the delta neighbourhood per unit. The choke price diverges from the market price of recyclable plastic bags whose value is currently pegged at R0.75 per unit. The difference between these two values can be imposed on the consumer as a levy so that the externality is internalized. Taking the first and second highest WTP associated (i.e., medium-sized and reusable shopping bags), the aggregated figure amounts to R7.11 per unit which is at least as high as the minimum price (R7.37) that respondents would consider for alternative packaging. Without other attributes factored in, this price (R7.11) might result in an inferior product since manufacturers are not taking into consideration the full range of attributes. Key informant interviews and FGDs revealed that a significant number of shopping bags that are found on the market are inferior as they break down easily. Furthermore, if we consider the medium-sized shopping bag and all the attributes of a shopping bag, we arrive at a maximum WTP of R12.01 per bag. Without loss in quality, the minimum price for a durable shopping bag of R7.37 is attainable if manufacturers are compensated for production costs. Policies such as a tax break or subsidies might assist in realizing such a significant reduction in the costs of durable shopping bags.
7. Conclusions
Single-use plastic bags are increasing becoming unpopular across the globe due to increasing plastic pollution which is threatening both terrestrial and marine ecosystems. The situation is even worse in developing countries and economies in transition such as South Africa where plastic consumption is fuelled by a combination of population growth and increasing household incomes resulting from the increased participation of women in the labour force and longer working hours. Interventions to reduce plastic consumption require objective information so that robust policies can be crafted to suit local conditions.
This study uses a choice experiment to elicit consumer preference for attributes of shopping bags from a sample of 250 consumers in Cape Town. Following the literature, we estimate two different models. First, we estimated the conditional logit model as the baseline model and perform appropriate tests to establish a model which fits our data. The Hausman–Mcfadden test was used to examine if the CLM violated the IIA assumption. Since the CLM violated the IIA assumption, we then proceeded to estimate the mix logit model or RPL model where the attributes interacted with the location.
Contrary to one stylized fact which paints poor people as being ignorant, unaware, and uninformed, we found awareness of plastic pollution to be very high among the surveyed respondents from low- to high-income areas. When asked about their preference for shopping bags, most respondents indicated that they would prefer durable shopping bags made of cloth. The highest price that respondents are WTP for non-durable (single-use) plastic bags is R2.92 per bag, while the minimum price that they would consider for alternative packaging is R7.37 per unit. This shows that there is room for increasing the plastic levy to force customers to internalize the externality. All attributes included in the model carry positive signs, except for large-sized shopping bags, implying that their presence enhanced the consumer’s utility. Large-sized plastic bags are less preferred compared to the status quo. Small-sized plastic bags are more preferred in low-income areas since they are relatively cheaper, while medium-sized packaging is more preferred in medium- and high-income areas.
According to the RPL model, the highest WTP is associated with the medium-sized shopping bag (R3.76), followed by a shopping bag that is reusable (R3.35), then a shopping bag that is styled (R2.16), a small-sized shopping bag (R1.74), a durable shopping bag (R1.50) and finally a recyclable shopping bag (R1.25). The low WTP value for recyclable shopping bags could be an indication that the respondents are not aware of recycling schemes. The WTP of a small-sized shopping bag that is recyclable is R2.99 which is equivalent to the maximum price that the respondent is offering for a single-use plastic bag (R2.92). Taking the first- and second-highest WTP associated (i.e., medium-sized and reusable shopping bag), the aggregated figure amounts to R7.11 per unit which is at least as high as the minimum price that respondents would consider for alternative packaging. Furthermore, if we consider the medium-sized shopping bag and all the attributes of the shopping bag, we arrive at a maximum WTP of R12.01 per bag.
Based on these results, the preferences of the sampled consumers in Cape Town do not tell us much about sustainable behaviour since the WTP values of durability and recyclability are low. Although not addressed in our study, the possibility of upcycling plastic bags as a sustainable solution to the disposal of shopping bags and contribution to the circular economy must not be underestimated as the growth of new ideas in this area can be promoted through awareness campaigns, learning, co-creation and competition to stimulate and reward innovation. Based on our results, we derive four policy recommendations.
Our results call for a combination of policy instruments such as a subsidy on expensive durable and reusable shopping bags to increase demand while at the same time increasing the levy on single-use plastic bags to reduce demand.
The message behind awareness campaigns and educational programmes should be carefully crafted to increase awareness of the benefits of upcycling and participation in recycling schemes rather than focusing only on plastic pollution and its negative effects.
Educational materials through television programs and internet-based platforms or social media could be used to enhance upcycling of plastic bags.
Policymakers can make use of the prices provided in this paper as an initial guide to the optimal value of the different types of plastic bags.