As surfactants from detergents continue to enter the Yamuna unchecked in the absence of regulatory limits, a new study by The Energy and Resources Institute (TERI) has identified multiple hotspots along the Delhi stretch of the river where untreated sewage, industrial effluents and solid waste are contributing to frothing, chemical contamination and a rising microplastic load.
The study, presented to the Delhi government on Tuesday, is based on nearly 100 water samples collected from more than 50 critical locations, including major drains, industrial clusters and sewage treatment plant (STP) outlets, during pre- and post-monsoon seasons.
A copy of TERI’s department-wise action plans or recommendations, accessed by The Indian Express, calls for continuous monthly monitoring of the Najafgarh and Shahdara drains and all major STPs and common effluent treatment plants (CETPs) for microplastic contamination, strict penal action against non-compliant treatment plants, and the installation of real-time plastic-pollution dashboards to track waste flows across the city. It also urged the government to plug untreated sewage discharges by completing drain-tapping projects and to upgrade underperforming STPs with advanced oxidation processes and biological nutrient removal technologies, needed to tackle the rising load of detergent chemicals and ammonia that current treatment systems struggle to remove.
The findings were reviewed at a high-level meeting chaired by Environment Minister Manjinder Singh Sirsa, where elevated levels of surfactants, organic pollution, ammonia and microplastics at several discharge points along the river were flagged. As the winter sets in and the Yamuna’s flow naturally dips, pollutants in the river become more concentrated, making the annual frothing more visible. When untreated sewage carrying both industrial laundry effluents and household discharge — including detergent-rich wastewater with high levels of surfactants — enters the river, they get vigorously agitated as the water falls over barrages. The turbulence traps air and reduces the water’s surface tension, causing bubbles to form quickly and accumulate as thick, persistent foam.
Sirsa directed all departments to examine TERI’s recommendations, identify priority hotspots and prepare time-bound implementation plans, and announced that a specialised inter-departmental coordination cell will be set up “to ensure integrated planning, execution and monitoring of Yamuna cleaning measures”. His office quoted him as saying: “I have instructed the departments to work in close coordination and remove procedural bottlenecks so that the people of Delhi can see visible changes on the ground at the earliest.”
Senior Delhi Jal Board officials, meanwhile, said the city currently has “no facility to treat excess amounts of surfactants” and that detergent content remains a “significant issue” driving frothing. “It will take a long time to control surfactants unless there is a determined limit for surfactant levels,” an official said, adding that six-eight STPs have been upgraded in recent months and the remaining are expected to be strengthened by December 2027.
Delhi-based environmental activist Pankaj Kumar said the continued absence of any regulatory cap on surfactants is rendering even upgraded treatment plants ineffective in tackling foam formation. “There is no limit set for surfactants. There has to be a national-level policy to set a maximum limit, and the government must also intervene at the manufacturing stage to ensure detergent formulations reduce surfactant content,” he said.
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Pointing to the Rithala 40 MGD Phase-II STP, which is one of the facilities upgraded to meet the latest Central Pollution Control Board norms, he said, “If frothing would have stopped just by upgrading, then the treated water coming out of Rithala STP would not have frothed. The plant shows compliance in DPCC reports, but the treated water coming out is still heavily frothed. This shows that the problem cannot be solved without regulating surfactants.”
Sophiya Mathew is a Correspondent at The Indian Express, based in New Delhi. She joined the Delhi bureau in 2024, and has specialization in Integrated Multimedia Journalism from the Asian College of Journalism (ACJ), Chennai.
Professional Background
Core Beats: Her reporting is primarily focused on the Environment and Education.
Specialization: She has gained recognition for her ground-level reporting on the Yamuna floodplains and the socio-economic challenges faced by those living on its banks. She also focuses on the disparities in Delhi's education system, ranging from elite private schools to government institutions and refugee education.
Recent Notable Articles (December 2025)
Her recent work has been heavily centered on Delhi's severe winter pollution crisis and the government's regulatory responses:
1. The Air Pollution Crisis
"A tale of two cities: Delhi govt schools choke in bad air, private classrooms set up air filters" (Dec 20, 2025): A high-impact feature contrasting the "Clean Air Bubbles" in elite schools with the reality of government school students who are exposed to an equivalent of 17 cigarettes a day due to outdoor exposure.
"Delhi sees season's worst air day, second worst December AQI in nearly a decade" (Dec 15, 2025): An analytical report on the meteorological patterns trapping pollutants in the NCR.
"Delhi bans non-BS VI vehicles from outside: Why curbing vehicular pollution is key" (Dec 17, 2025): Explaining the science behind targeting specific vehicle vintages to lower particulate matter.
2. Enforcement & Regulations
"No fuel at pumps in Delhi without valid PUC certificate from December 18" (Dec 17, 2025): Breaking the news on the environment ministry's strict "No PUC, No Fuel" policy.
3. Education Policy
"Law to regulate school fee in Delhi risks becoming procedural, say parents" (Dec 13, 2025): Investigating the loopholes in the new Delhi School Education (Transparency in Fixation and Regulation of Fees) Bill, 2025.
"Monsoon Session: Private school fee regulation Bill cleared after four-hour debate" (Aug 9, 2025): Covering the legislative passage of the controversial fee hike regulation.
Signature Style
Sophiya is known for her observational depth. Her reporting often includes vivid details from school corridors, hospital waitlists, or the banks of the Yamuna to illustrate how policy failures affect the city's most vulnerable residents. She is a frequent expert guest on the 3 Things podcast, where she explains the complexities of Delhi’s environmental laws.
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