- A recent study on emissions from macroplastic pollution, finds that India produces nearly 9.3 million tonnes (MT) of macroplastic waste emissions every year, followed by Nigeria, Indonesia and China.
- The study identified emission hotspots across 50,702 municipalities worldwide from five land-based plastic waste emission sources.
- Uncollected waste accounts for 68% of all plastic waste emissions in the Global South.
A recent study published in the journal Nature, found that emissions from plastic pollution are the highest in India, with the country contributing to nearly one-fifth of global plastic emissions. The study, conducted by researchers at the University of Leeds, has created the ‘first ever global inventory of macroplastic pollution’. It names ‘uncollected plastic waste’ and ‘uncontrolled burning’ as the biggest causes of plastic pollution emissions. India tops the list, producing nearly 9.3 million tonnes (MT) of macroplastic waste emissions every year, followed by Nigeria (3.5 MT), Indonesia (3.4 MT), and China (2.8 MT).
This study defines macroplastic (plastic particles > 5 mm) emission as “material that has moved from the managed or mismanaged systems in which waste is subject to a form of control, however basic (contained state) to the unmanaged system or the environment (uncontained state) with no control.” It further classifies emissions in two categories: debris, which is physical particles bigger than 5 mm and open, uncontrolled burning.
According to the study’s methodology, India has been overestimating its waste collection coverage and underestimating its official waste generation rate. The authors believe this to be the case because the official statistics do not include rural areas, open burning of uncollected waste or informally recycled waste.
The flow of plastic waste
The study had a pointed, single-format focus on macroplastic emissions. The authors say that while “plastic pollution exists in many forms (macroplastic debris, air pollution, GHG emissions, chemicals and microplastics), it is implausible to quantify all of these in a single piece of work.”
The study excludes emissions from construction and demolition, industrial plastic waste and sewage treatment, textiles, electrical and electronic equipment waste, and waste material arising at sea.
It also strictly includes only the ‘downstream’ part of plastic pollution. In the language of plastics lifecycle, the term ‘upstream’ usually describes activities directed at the stage of raw material extractions such as oil and gas, and plastic production. ‘Midstream activities’ refer to design, manufacture, packaging, distribution and use, and ‘downstream activities’ focus on the end-of-life management of plastics such as segregation, collection, sorting, recycling and disposal.
The study uses a bottom-up approach, modelling plastic flows at the municipal level. It focuses on the flow of waste generated from households, commerce, trade, small businesses, office buildings and institutions (schools, hospitals, government buildings).
Using machine learning and probabilistic material flow analysis, the study identified emission hotspots across 50,702 municipalities worldwide from five land-based plastic waste emission sources — uncollected waste; littering; collection system; uncontrolled disposal; and rejects from sorting (recycling system).
The researchers employed four different global datasets including data from the World Bank and the United Nations, and two national databases in this study, to create a city-level solid waste management database with worldwide coverage. “The two national databases were used to increase the sample sizes for China and Indonesia, where municipal scale data were lacking. Including those enabled a more representative sample form the machine learning model,” the authors said.
Uncollected and burned plastic waste paves the way for enormous emissions
According to the study authors Joshua Cottom, Ed Cook and Costas Velis, “modelling the study at municipal scale allows to focus on a resolution at which waste is managed and at which waste data are measured. Quantification of municipal waste flows begin at the point of waste generation.”
The authors state that in the Global South, “waste generation is often estimated by counting trucks entering the disposal sites and applying assumptions. Aside from the inaccuracy of this method.” They add, “It does not account for the many other pathways through which waste flows. For example, waste which has not been collected is often burned, buried, dumped into waterways, or deposited on the surface of the land. The informal recycling sector also collects valuable materials, sometimes before they leave the premises of the household or business in which they were generated.”
Overall, the study found that the difference of emissions in plastic waste between the Global North and Global South countries, is stark. While littering is a major problem in the former, uncollected waste and uncontrolled burning were huge issues in the latter. The study also indicates that uncollected waste accounts for 68% of all plastic waste emissions and 85% of all debris emissions in the Global South.
The authors state that understanding the mechanisms of plastic emission and gaining insights into the nature, scale, and causes of plastic pollution will support the creation of evidence-based action plans at national and sub-national levels to eliminate plastic from our environment. “Our study highlights the spatial location at which plastics pass from human controlled systems and into the environment. Our data will enable countries to target their resources where the problems are most acute,” they add.
On alleged gaps in the study
This study has been criticised by Break Free From Plastic (BFFP), a global non-profit advocacy group working against plastic pollution, for blaming the Global South while overlooking the role of the global waste trade in adding to the problem of plastic pollution. The outfit, in a press release published on their website, states that “Data from the Basel Action Network (BAN) shows that Malaysia, Indonesia, India and other less industrialised nations are among the top destinations for plastic waste generated in the Global North. These same countries then get blamed in the study for being top plastic polluters.”
The authors told Mongabay India, “Our ‘bottom-up’ approach means we can more accurately describe the detailed and complex processes that take place at a high spatial resolution. Because it works at a municipal scale, it is not compatible with incorporating national scale measurements such as transboundary movements (imports and exports) and plastic production,” They explained that their study stated that imports and exports were excluded as this may lead to an underestimation of emissions for some high-income countries. “We also presented data which explicitly show that the impact on emissions would be very small in comparison to the overall mass of emissions worldwide. We are aware that International Pollutants Elimination Network (IPEN) has carried out research that suggests that plastics exports using the HS3915 code (the code for waste and scraps of plastic exported) only show a part of the picture, but even accounting for the scaled increase their model infers would not substantially increase the emissions burden from exports.”
The study authors strongly recommend the use of their research to mobilise the necessary resources from the Global North (those involved in the production and retail of plastics at all levels via e.g., Extended Producer Responsibility schemes). In response to criticism from BFFP, they said, “We would strongly suggest that BFFP totally revises its approach and uses our research to enable countries, citizens, grassroots organisations, and legal considerations by offering novel insights and the mechanism to mitigate plastic pollution at scale.”
“On reflection, we recognise that aspects of our original media release might have been better phrased. We place the greatest importance on accuracy and have amended our media release accordingly,” they added. The original media release was updated to correct some errors in phrasing the sentences related to Global South countries.
The study comes at a time when negotiations on a global treaty on plastic pollution are round the corner, slated to take place on November 5, 2024. The study is likely to have an impact on the negotiations.
Read more: PlastiCities: the role of grassroots initiatives in managing waste in cities
Banner image: Garbage collection truck. Image by Arne Hückelheim via Wikimedia Commons (CC BY-SA 3.0).
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