Mountains of solid waste in landfills and rivers of plastic in oceans have become a symbol of modern society, more so in developing countries.

Asia is responsible for 71% of the world’s mismanaged plastics (Neo et al., 2021) with India ranking 12th in the world (Shanker et al., 2022). In contrast, several studies have determined that India has one of the world's highest plastic waste recycling rates, between 40-60% (Shanker et al., 2022). These two seemingly contradictory pictures make India, an interesting choice for a case study on plastic waste management in the developing context.

There are unrecognised warriors in the Global South who have been instrumental in achieving high plastic recycling rates. These are the informal waste workers who work outside the mainstream formal system and collect recyclable material from households, garbage dumps, or even landfills directly. In fact, India owes its successful plastic recycling rate in part to the informal sector.

While there have been studies to quantify the plastic waste management system of India, there is little known about the extent of the contribution of the informal sector to plastic recycling due to the ‘invisible’ nature of its operations.

This study attempts to expand the existing body of knowledge on the contribution of informal sectors in achieving high plastic waste recycling rates in India, by focusing on the test case of the city of Chennai in South India.

In that regard, this paper aims to address the following two sub-research questions related to the plastic recycling value chain: (1) What are the material flows of household plastic waste along the formal and informal recycling value chain of plastic waste in Chennai, and where do exchanges between the two sectors occur? (2) What are the data gaps in estimating the material flows, and the barriers and challenges in building a comprehensive MFA of plastic waste in the developing context?

To answer the first question, the tool Material Flow Analysis (MFA) is used to estimate the recycling value chain of plastic waste generated in Chennai. The plastic waste flows from the stage of waste generation in households to End-of-Life management are covered. The interplay between formal and informal waste sectors is included wherever present. To obtain data for the MFA model, secondary data from peer-reviewed literature, and other literature like reports, government publications, etc. are combined with primary data collected via field visits and interviews with experts.

Data unavailability is one of the biggest barriers to building a comprehensive MFA of plastic waste management system in Chennai, particularly the contribution of the informal sector. Thus, qualitative data obtained from the interviews about the barriers to data collection and the social issues that keep the system hidden from the outside is used to discuss the second research question. Finally, possible solutions to circumvent these issues are explored to promote the flow of information among internal and external stakeholders to envision a more effective and fair plastic waste management system.

The study highlights the importance of involving informal waste pickers in the plastic waste management process, as they play a significant role in achieving a circular economy through recycling plastic waste. By recognizing the contributions of the informal waste sector, this study also aims to improve the lives of waste pickers and promote their inclusion in the formal waste management sector.