26 of 27 Yamuna-bound drains fail water quality norms: DPCC
The Delhi government plans to connect all households to sewage treatment plants and double overall treatment capacity over the next three years
As Delhi moves to modernise its infrastructure to improve the Yamuna’s water quality, untreated sewage and industrial effluents continue to heavily pollute the drains flowing into the river, according to the latest report by the Delhi Pollution Control Committee (DPCC).
The report for the month of October, found that of the 27 drains assessed, 10 had no flow or had been tapped. Of the remaining 17 drains, only one — the Shastri Park drain — met the prescribed water quality standards.
Senior government officials said the Delhi Jal Board (DJB) is planning to step up surveillance of water quality in 75 drains and sub-drains that carry untreated effluents into the river.
Under the current system, authorities monitor parameters such as pH, biochemical oxygen demand (BOD), chemical oxygen demand (COD) and total suspended solids (TSS) in drain samples across Delhi-NCR. BOD indicates organic pollution by measuring the oxygen required by microorganisms to break down biodegradable matter, COD measures the oxygen needed for chemical oxidation of pollutants, while TSS reflects water turbidity due to undissolved particles. Lower values indicate better water quality.
According to DPCC standards, drain samples should have a pH between 5.5 and 9, TSS below 100 mg/L, COD below 250 mg/L and BOD below 30 mg/L.
The Sahibabad drain, from Uttar Pradesh, was found to be the most polluted, recording the highest BOD at 145 mg/L, COD at 416 mg/L and TSS at 200 mg/L. Other heavily polluted drains include the Sen Nursing Home drain, Maharani Bagh drain, Shahdara drain and the drain near Sarita Vihar.
The Najafgarh drain, which carries the highest volume of wastewater into the Yamuna, recorded a TSS of 140 mg/L and BOD of 60 mg/L.
The DPCC report also noted that the 22-km stretch of the Yamuna between Wazirabad and Okhla is the most polluted section of the river, with 22 major drains discharging into it. Officials said the DJB is currently unable to treat the entire volume of sewage generated in the city, resulting in large quantities of untreated waste entering the river.
To address this, the Delhi government plans to connect all households to sewage treatment plants and double overall treatment capacity over the next three years, officials said.
A DJB official said the utility is also launching a comprehensive initiative to identify and curb wastewater discharge. “The primary source of pollution is the network of drains originating from Delhi and neighbouring states that empty into the Yamuna. We have decided to study 75 drains and sub-drains discharging into the river,” the official said.
The study will specifically examine 13 drains entering from Haryana, including Mungeshpur drain, Drain No. 6 near the Narela border as well as Alipur Link drain.
Diwan Singh, an environmental activist who led the Yamuna satyagraha for rejuvenating the river and other water bodies in the city, said that these drains and sub-drains had been monsoonal nallah that fed Yamuna but they have been rendered into sewage carrying channels. “We need to tackle the pollution sources at sub drain level by treating the drain as a system in itself. We can used twin strategy of setting up decentralised treatment plants as well as in situ treatment of drains but the sources need to be tapped. It does not take many tests to see that Delhi’s drains are carrying extremely polluted wastewater.”
Delhi's efforts to improve Yamuna's water quality face challenges, as a DPCC report reveals that 10 of 27 drains assessed had no flow, and only one met water quality standards. Heavily polluted drains include Sahibabad and Najafgarh, with untreated sewage entering the river. The Delhi government plans to enhance sewage treatment capacity and monitor 75 drains to combat pollution.