New Delhi: The monsoon rain that Delhi got this year failed to improve Yamuna’s water quality. Several monitoring points recorded higher pollution in the river in Sept this year than at the same time last year, a Delhi Pollution Control Committee (DPCC) report shows.At ISBT Bridge, the Sept 7 sample recorded a biochemical oxygen demand (BOD) of 30 mg/l, compared with 8 mg/l on Sept 3 last year. Chemical oxygen demand (COD) rose from 44 mg/l to 92 mg/l over the same period. The reported fecal coliform count also increased from 2,800 to 35,000, which is a rise of 12.5 times.A BOD limit of 3 mg/l or less and dissolved oxygen of at least 5 mg/l are specified for bathing. For fecal coliform, the desirable limit is 500 MPN/100 ml, with 2,500 MPN/100 ml as the maximum permissible level.At ITO Bridge, BOD climbed from 4 mg/l to 18 mg/l, while COD rose from 20 mg/l to 60 mg/l. Fecal coliform levels increased from 1,800 to 17,000 MPN/100 ml.The monsoon brought less rainfall to Delhi this Sept than the last one. Though the net rainfall was above normal in 2025 and 2026, the river did not cross the danger mark this year, unlike last year. The rainfall figures offer an important point to the context of yamuna pollution, but they do not by themselves explain the deterioration.The volume of flowing water, upstream releases, the timing and intensity of rain, and the quantity of sewage entering the river can all influence measured pollution levels.
