Cauvery river contaminated as banned plastics continue to flow: Norwegian report

 

A major new scientific report reveals that Tamil Nadu has emerged as India's largest contributor to plastic waste, generating approximately 7.82 lakh tonnes annually and accounting for nearly one-fifth of the nation's total plastic pollution, despite having only six percent of India's population. The report, titled "Reducing Plastic Pollution in Tamil Nadu, India: A Science-Based Strategy," was released under the India-Norway cooperation project INOPOL, a collaborative effort between the Norwegian Institute for Water Research, Mu Gamma Consultants, and the Central Institute of Petrochemicals Engineering and Technology.

According to data submitted by the Tamil Nadu Pollution Control Board to the Central Pollution Control Board, the state generated approximately 2,144 tonnes of plastic waste daily during the financial year 2022-23. While officials report that 96.22 percent of this waste is collected and 90 percent is processed, field monitoring tells a more troubling story. The report states that whilst 96 percent of plastic waste is collected in the state, on average 81 tonnes goes uncollected each day, corresponding with 29,585 tonnes of plastic waste that is not collected over the course of a year.

The Cauvery River, which flows through Tamil Nadu covering 54 percent of the basin, has become a critical pollution hotspot. Monitoring conducted across six sites during three seasonal campaigns revealed alarming levels of macroplastic contamination. The monitoring, conducted during the northeast monsoon of November 2024, the dry season of February 2025, and the southwest monsoon of September 2025, documented that 51.7 percent of all plastic waste observed in the Cauvery catchment was packaging material, with food packaging being the most dominant type. The report notes that packaging represents the dominant type of plastic litter observed, with sachets representing the majority at 31.1 percent within this category.

Direct dumping of waste into the river remains a critical issue. During 11.6 percent of visual observation measurements, people were observed discarding one or more bags of litter from the bridge directly into the river channel. Despite India's ban on single-use plastics introduced in 2016 and expanded in 2021 and 2022, the study found that 19.3 percent of observed macroplastic litter consisted of banned single-use plastic items, predominantly plastic bags below the legal minimum thickness of 75 to 120 microns. Measurements confirmed that most bags recovered ranged between five and 20 microns, far below legal requirements.

Micro, Small and Medium Enterprises are central to both the problem and potential solutions. Tamil Nadu hosts approximately 15 percent of India's registered factories, with 26 percent of registered entrepreneurs being women, reflecting strong potential for inclusive solutions. However, these enterprises face significant challenges. The report identifies regulatory pressures and adaptive capacity as major concerns, noting that frequent regulatory revisions to the Plastic Waste Management Rules and single-use plastic restrictions create uncertainty, especially for small actors with limited administrative capacity.

Andreas B. Schei, Counsellor for Climate and Environment at the Royal Norwegian Embassy in New Delhi, writes in the report's foreword that this strategy report demonstrates that strong cooperation between Indian and Norwegian technical institutions can generate scientific knowledge that can lead to practical pathways for action.

The report proposes a comprehensive, phased implementation strategy. Short-term priorities from 2025 to 2026 include completing state-wide baseline surveys, establishing State and District Plastic Waste Task Forces, commissioning more than 100 new Plastic Waste Management Units, achieving 100 percent source segregation in Urban Local Bodies, and achieving more than 30 percent recycling rate through expanded Material Recovery Facilities. Medium-term goals from 2027 to 2028 include a 50 percent reduction in single-use plastic items in use, establishing more than 500 active Plastic Waste Management Units across the state, achieving 40 to 50 percent plastic recycling rate, and ensuring less than 10 percent plastic waste goes to landfill or incineration. Long-term vision from 2029 to 2030 and beyond includes integration of plastic credits market under Extended Producer Responsibility, aiming for plastic-neutral industries where producers offset usage through recovery, and consolidating circular systems with near 100 percent collection efficiency.

The report introduces an innovative INCA-Macroplastic modelling tool, available online through the International Knowledge Hub against Plastic Pollution, allowing users to visualize how changes in population density, waste generation rates, and mitigation measures affect plastic pollution outcomes. Thorjorn Larssen, Deputy Chief Executive Officer of NIVA, emphasizes that plastic pollution is a systemic challenge that cuts across environmental protection, public health, and resource efficiency, and through environmental monitoring, modelling, and system analysis, the INOPOL partnership has generated an evidence base that can support more effective plastic waste and pollution management.

The report outlines several actionable recommendations including improved monitoring of single-use plastic ban compliance, particularly for plastic bags below minimum thickness, inclusion of additional items in the single-use plastic ban such as sachets and various packaging types that dominate river waste, awareness campaigns and improved waste collection to limit direct dumping especially at riverbanks and bridges, investigation of check dams and barrages as potential waste capture technologies, and strengthened Extended Producer Responsibility implementation through improved registration, auditing, and accountability.

The report concludes that the findings suggest that reducing plastic pollution requires more than the expansion of infrastructure or the introduction of new regulatory instruments, and persistent leakage points to systemic challenges that cut across policy implementation, enforcement capacity, economic incentives, social practices, and institutional coordination.