Yamuna pollution remains severe in Delhi despite improvement at some points

The April report showed slight improvement at Asgarpur, but levels of faecal coliform remained as high as 3,10,000 Most Probable Number per 100 millilitres MPN100 ml, as compared to 4,00,000 MPN100 ml in March.

The latest Delhi Pollution Control Committee (DPCC) data on the Yamuna's water quality for April shows a further rise in faecal coliform levels at certain stretches of the river compared to March, indicating that a significant amount of untreated sewage is entering the river. The report also shows high levels of Biological Oxygen Demand (BOD), a measure of the amount of dissolved oxygen required by microorganisms to break down organic matter in water -- a higher BOD value indicates higher levels of pollution, often leading to oxygen depletion and harm to aquatic life. The DPCC's water quality testing involves collecting samples from eight locations along the course of the Yamuna through the national capital and measuring parameters such as BOD, dissolved oxygen, chemical oxygen demand, pH, and faecal coliform, to determine pollution levels. These eight locations include Palla, Wazirabad, ISBT Bridge, ITO Bridge, Nizamuddin Bridge, Hindon Cut, Okhla Barrage, and Asgarpur in Kidwali, Haryana. While four of the points showed slight improvement in faecal coliform levels, the numbers still remained firmly above the permissible limit of 2,500 and the desirable level of 500. The April report showed slight improvement at Asgarpur, but levels of faecal coliform remained as high as 3,10,000 Most Probable Number per 100 millilitres (MPN/100 ml), as compared to 4,00,000 MPN/100 ml in March. The level at the same site was 3,50,000 MPN/100 ml in January and 92,000 MPN/100 ml in February 2026. The three other locations which showed improvement were Palla, where the level of faecal coliform improved from 3,200 MPN/100 ml in March to 2,800 MPN/100 ml in April; Hindon Cut, where the level improved from 80,000 MPN/100 ml to 54,000 MPN/100 ml; and Okhla Barrage, where the level went from 2,00,000 MPN/100 ml in March to 1,20,000 MPN/100 ml in April. At Wazirabad, however, the level of faecal coliform increased in April, and touched 9,200 MPN/100 ml, as compared to 4,300 MPN/100 ml in March. At ISBT Bridge, the level was 1,70,000 MPN/100 ml as compared to 1,60,000 MPN/100 ml in March; the water collected near ITO Bridge showed a level of 1,50,000 MPN/100 ml in April; and at Nizamudin Bridge, the level was 1,40,000 MPN/100 ml in April. BOD levels for April also showed alarming readings, ranging from 3-58 milligrams per litre (mg/l), while the water quality criteria stipulated a maximum of 3 mg/l, with the highest BOD recorded at Asgarpur at 58 mg/l. The BOD at Asgarpur last month was 60 mg/l. The DPCC has also uploaded the data for Delhi's drains for April, while the data on analysis of sewage treatment plants (STPs) and common effluent treatment plants (CETPs) for April are yet to be uploaded. The wastewater quality status of several drains discharging directly into the Yamuna, as well as supplementary drains of the Najafgarh drain, showed high BOD and COD levels as well.