1. Introduction
India is the fastest growing economy and the second most populated country in the world. The present annual quantity of solid waste generated in Indian cities has increased from six million tons, in 1947, to 48 million tons, in 1997, and to 90 million tons in 2009; this is expected to increase to 300 million tons by 2047 [
1,
2,
3]. This massive increase in the amount of municipal solid waste (MSW) generated is because of changing lifestyles, food habits, and the standard of living of the urban population [
4]. The characterization of MSW has indicated that the waste consists of 30%–45% organic matter, 6%–10% recyclables, and the rest is inert matter [
5].
The collection of MSW is primarily the responsibility of corporations/municipalities. However, many municipalities have provided contracts to private waste management companies for secondary transportation from community bins to disposal sites. Others have employed non-governmental organizations (NGOs) and resident associations to supervise and arrange segregation and collection from the point of generation to collection points, by charging a collection fee to residents [
6]. The community bin (dhalao) collection system is adopted in most cities in India. It is a primary storage facility, in the form of a waste receptacle, provided by a municipality [
5]. On an average, there are about two to three collection points per square kilometer [
4].
The inhabitants of Delhi generated about 4000 tons per day of MSW in 2000, 6800 tons per day in 2011 [
7], and 8360 tons per day in 2015 [
8]. The quantity of waste in Delhi is expected to increase to 17,000–25,000 tons per day by 2021 [
9]. Approximately 70%–80% of generated MSW is collected, and the rest is disposed of as open dumps on the streets. Only 9% of the collected MSW receives treatment through composting, which is the only treatment option, and the remaining mixed waste is disposed of in open landfills at the periphery of the city. Composting plants are not presently operating to their intended treatment capacities. In the absence of leachate and landfill gas collection systems, these landfills are a source of groundwater contamination, as well as of air pollution [
4]. The low calorific value of waste, the presence of inert material, as well as construction and demolition waste in municipal solid waste, makes it inappropriate for incineration of waste for energy production. Therefore, the lack of waste segregation at the source of waste generation has been identified as a major hurdle in the further treatment and disposal of waste [
10].
In the past, to facilitate the segregation of waste at the household level, the government introduced the MSWRules 2000 and the Bhagidari—a citizen-government partnership. The purpose of Bhagidari was to develop awareness, public participation, and to improve segregation and the primary collection of the waste [
4]. However, it failed to introduce segregation due to a lack of public cooperation [
11]. To facilitate the participation of the residents of Delhi, a greater generation of awareness and the promotion of motivation is essential [
12].
The Municipal Corporation of Delhi recognizes that there is an extensive network of informal and formal stakeholders who collect waste, such as paper/cardboard, metals, glass, leather, plastic, rubber, textiles, etc. Recyclables are collected by rag pickers from dhalaos, or landfills, and are passed into the recycling stream. Households also directly sell recyclables to itinerant buyers. It is estimated that there are 80,000–100,000 rag pickers in Delhi, and, assuming that a rag picker picks up 50 kg of waste each day, it reduces the burden for treatment, as well as disposal, by 1200–1500 tons per day [
13]. The total number of itinerant buyers in Delhi is estimated to be about 18,000–20,000 [
13]. The quantity of waste sold to these buyers is unknown, but is expected to be, approximately, as much as that collected by rag pickers. Although the contributions of waste pickers and collectors for conserving the city’s environment, and for reducing public cost, is significant [
14], recycling by the informal sector is done in an unhygienic manner, causing air, groundwater, and soil pollution [
13].
In Delhi, households are the largest source of solid waste generation [
15], and there is very low compliance to rules regarding municipal solid waste management [
7]. In such a situation, it becomes important to understand the level of knowledge possessed by the residents of Delhi regarding solid waste management. The importance of resident knowledge, and adequate facilities for public participation in waste management, has been established by studies conducted in other countries, such as Brazil [
16], Italy [
17,
18], and Spain [
19]. In addition, social and psychological factors may also play a crucial role in promoting public participation in waste management. In a case study conducted in a Greek island community, social factors were seen to influence perceptions and willingness to pay for solid waste management [
20]. In the city of Nisshin, Japan, it was found that the expectation of personal empowerment, a sense of self-efficacy and solidarity, was the main determinant of the behavioral intention of citizen participation [
21].
Several other studies have highlighted the waste management behavior of households in countries, such as UK [
22,
23], Iran [
24], Malaysia [
25], and Greece [
26], using the framework of the theory of planned behavior, to understand the attitudes, subjective norms, intentions, and perceived behavioral controls of residents. A social survey conducted in Malaysia revealed that people have a positive intention in participating in source separation of food waste in the household, if they are given the knowledge, opportunities, and facilities needed regarding source separation [
25]. A study in Iran indicated that educational material that targets moral obligation and action planning may be more effective in improving household waste reduction behavior [
24]. A study done in the UK also suggests that a pro-recycling attitude is the major contributor to recycling behavior [
22,
23]. These attitudes are influenced by the availability of appropriate facilities and knowledge, apart from other factors, such as concern for the community and previous recycling experience. Research on resident knowledge, attitudes, and action regarding solid waste management in India is limited, and the influence of socio-economic factors on these attitudes has scarcely been investigated. In a study conducted in a town, in the southern state of Tamil Nadu in India, it was found that the monthly income of a household has a strong positive correlation with the disposal of vegetable waste. Monthly income has strong negative correlation with the presence of a dustbin at home and the reuse of items. The age of respondents is negatively correlated with waste segregation [
27]. In the city of Bangalore, India, it was found that household income was positively correlated with a willingness to pay for waste management [
28]. In another study conducted among the urban poor, in a slum of Jammu, it was revealed that a majority of the respondents had a high level of basic environmental awareness and that there were significant differences in environmental awareness levels among male and female respondents, but there were no significant differences among the different age groups [
29]. A survey conducted in selected areas of the city of Coimbatore in South India, captured the perception of households, but did not explore the differences among socio-economic categories [
30]. All of these studies have suggested a need for improving the knowledge of residents regarding waste management. However, these studies explore only a few aspects of knowledge and attitude. Moreover, the attitude and culture of the residents of the capital city of Delhi are very different from those explored in the existing literature.
Knowledge has been seen as a key variable affecting environmental action [
31,
32]. It has been argued that higher levels of environmentally relevant knowledge play a significant role in modifying environmental behavior [
33,
34]. Schahn and Holzer [
35] follow two definitions of knowledge in their research on recycling: abstract knowledge (AK), which focuses on awareness of general environmental issues, and concrete knowledge (CK), which evaluates awareness of local services, for example, recycling services [
36]. In this research, we modify these definitions further, and understand AK as knowledge regarding general issues regarding waste management, and define CK as knowledge regarding issues specific to waste management in Delhi. Knowledge is an important predictor of behavior, as a lack of knowledge will lead to a decline in self-efficacy, and then lead to the feeling that the individual cannot participate because they lack the knowledge required to take part [
36]. In the present research, we will utilize these definitions of abstract knowledge and concrete knowledge.
The objectives of the present study are summarized as follows. Firstly, this research seeks to explain the situation in Delhi with respect to segregation, storage, collection, and disposal of solid waste. Secondly, an attempt is made to understand the relationships between: (1) abstract knowledge and the willingness to engage in waste management; (2) concrete knowledge and willingness to engage in solid-waste management; and (3) willingness to engage in solid-waste management and waste segregation. Thirdly, this research also explores how resident knowledge varies among different socio-economic categories. This research does not explore all other situational and psychological factors that determine behavior, as the focus of this study is to explore resident knowledge regarding waste management.
4. Recommendations and Conclusions
The primary problem regarding waste management in Delhi is a lack of segregation at the source. This is inevitable, as most residents do not know the difference between biodegradable and non-biodegradable waste. Beginning at the household level, each household should segregate waste into two bins (dry/non-biodegradable and wet waste/biodegradable). This is logically possible as most households in this study had a bin inside the house (
Table 3). Further segregation into biodegradable, non-biodegradable, and domestic hazardous waste, as suggested in Solid Waste Management Rules 2016, will only be possible once residents recognize the basic difference between biodegradable and non-biodegradable waste. It should be noted that preventing mixing of waste by doorstep waste collectors is very important, as the current survey revealed that people do not segregate their waste because waste collectors mix the waste during collection (
Table 3). Old newspapers are sold to Kabariwalas, or itinerant waste buyers, as they can be stored in a convenient location in the house, taking up little space in a corner of the house, as they do not require cleaning before storage, unlike glass bottles/plastic oil cans. Financial incentives or extrinsic motivation drives residents to segregate their waste, since a majority of the respondents answered that the reasons for selling waste to Kabariwala was due to the value of the waste (
Table 3).
The Residents Welfare Association (comprising women and the elderly) could also monitor and supervise segregation, recycling, and composting in their residential areas and ensure that the doorstep collector collects segregated waste from households, as the survey shows that a majority of the households already have a doorstep collection service. Such an arrangement would involve the active participation of groups with higher abstract knowledge (elderly, women, and the lowest and highest socio-economic categories). Community-based management programs have successfully diverted waste from landfills, as exemplified in Thailand [
58]. Replication of such models would go a long way in ensuring the economic, environmental, and social sustainability of waste management in Delhi.
As revealed in discussions with NGO representatives in Delhi, in the past, there has been a failure in reaching out to the common people due to the absence of adequate and appropriate advocacy tools and sustained awareness campaigns, targeting different sections of the population. It would be essential to impart general knowledge (abstract knowledge) regarding waste management to residents, since abstract knowledge is significantly correlated with a willingness to engage in waste management. In order to encourage source segregation there needs to be interesting awareness campaigns focusing on waste management as a public health issue, and highlighting its impact on environmental pollution. In addition, there should be agreements with waste workers, such as incentive mechanisms and penalties for non-compliance, as suggested in the Solid Waste Management Rules 2016 [
40]. Sliding fiscal incentives, based on non-segregation, may go a long way in ensuring that residents segregate their waste. A household that segregates 80% of the days, should be asked to pay less doorstep collection fee than a household that segregates 50% of the days. In addition, there can be non-monetary incentives, such as rewards for households that segregate their waste, or for residential areas which have a high percentage of segregating households. Residents need to see the benefits of source segregation of waste in order to be encouraged to segregate; for example, if they see their dry waste getting recycled and compost being generated out of their wet waste (and that compost is being used in their gardens) then they may understand the value of segregation.
To improve waste management in Delhi, it would be important to ensure the involvement of all stakeholders. NGOs and RWAs can help in conducting awareness campaigns and facilitating doorstep collection in a systematic manner. Additionally, the government can provide space and facilities for MRFs. Private waste management companies can help in the regular transport of waste, and in the processing of hazardous domestic waste. Companies manufacturing products with potential for extended producer responsibility can collaborate with the Kabariwala network in order to facilitate proper collection. Segregation at the source would significantly reduce the burden on waste collection vehicles, from community bins to landfills, as they would only be responsible for the transportation of hazardous waste to a centralized processing facility, and to take inert waste to landfills. Further research can elaborate the specific details of such a model for Delhi.