White as a sheet: Delhi’s Yamuna froths again, data missing

New Delhi: The Yamuna is once again blanketed with thick white froth at Kalindi Kunj, an unmistakable and alarming visible proof of severe pollution that has quietly returned to the river stretch in Delhi. While both stench and foam are back, the urgency to remediate them is missing.Unlike last Oct, when Delhi govt swung into action ahead of Chhath Puja with daily inspections and heavy freshwater releases from Hathnikund Barrage, the current response is marked by silence. Delhi Pollution Control Committee (DPCC) is also yet to release any river water quality assessment for Jan or offer any explanation for the delay.The Yamuna pollution had dominated public discourse during the 2025 Delhi Assembly elections, with parties sparring over sewage treatment failures and river rejuvenation promises. The massive freshwater releases from Hathnikund Barrage had temporarily diluted pollutants last Oct, banishing froth and odour, but it remained cosmetic and event-driven."Wastewater is not being treated. That's why frothing is visible again," said environmental activist Pankaj Kumar. "In Oct, the river had nearly 10 cusecs of freshwater flow. Now it is virtually nil. Almost all wastewater generated in Delhi-NCR is reaching the river untreated or poorly treated," he alleged.Experts point out that structural factors worsen the problem. The ITO gates remain permanently open while barrages like Kalindi Kunj trap pollutants like surfactants and phosphates. TOI reported in Jan how experts raised questions over the credibility of DPCC's Yamuna reports for Nov and Dec 2025, which were also delayed. While the reports claimed improvement compared to last year, several indicators did not align with ground reality. For instance, at Kalindi Kunj, biochemical oxygen demand (BOD) — the river's capacity to heal itself — reportedly improved in Nov and Dec, even as frothing and stench returned after freshwater releases stopped."How can the river appear visually clean in Oct, but show worse BOD readings than Nov and Dec when froth returned?" Kumar asked, calling the data "illogical".Several drains also recorded BOD levels exceeding 100mg/l, yet corresponding river stretches showed improvement in official data. TOI had reported the same in Nov 2025 and this Jan while DPCC did not respond to queries.Environmentalists warn that with the river out of the political and festive spotlight, monitoring appears to be slipping. Central Pollution Control Board does not independently assess the Yamuna in Delhi and relies on DPCC's data."The Yamuna was treated like a tap — turned on for elections and festivals, then shut off," said river activist Bhim Singh Rawat. "Without year-round environmental flows and functional sewage treatment plants, frothing will remain a permanent feature." Centre, however, along with Delhi govt, recently reviewed three dam projects on the Yamuna — Lakhwar in Uttarakhand, Renukaji in Himachal Pradesh and Kishau on the border of both states. The projects, stalled over 25 years, are expected to bring e-flow to the river, diluting pollutants. Even in Oct, the pollution level was way above standards.