New Delhi, Sept. 18 -- New Delhi The Yamuna showed a marked improvement in several water-quality parameters in August, with increased monsoon flow helping dilute pollutants, even as contamination remained above prescribed limits at most points in Delhi, according to the latest assessment by the Delhi Pollution Control Committee (DPCC).

The report, dated September 9, recorded a substantial fall in faecal coliform, an indicator of sewage contamination, at multiple monitoring stations. At Asgarpur, at the downstream end of Delhi, the level dropped from 3.2 lakh MPN/100ml in July to 3,600 MPN/100ml in August. At Okhla Barrage, it fell from 1.1 lakh to 23,000 MPN/100ml.

However, both figures remained considerably higher than the Central Pollution Control Board's benchmark of below 2,500 MPN/100ml. The prescribed limit was met only at Palla and Wazirabad, where faecal coliform was recorded at 1,400 and 1,100 MPN/100ml, respectively. Wazirabad had recorded 3,500 MPN/100ml in July.

The improvement was also visible in dissolved oxygen (DO), which had dropped to zero between ISBT Kashmere Gate and Asgarpur in July. In August, oxygen was detected throughout the stretch, although levels varied considerably. DO was 6.8mg/L at Palla and 5.7mg/L at Wazirabad, compared with 3mg/L at ISBT, 5mg/L at ITO, 4.6mg/L at Nizamuddin, 4mg/L at Okhla and 2.6mg/L at Asgarpur.

Biochemical oxygen demand (BOD), however, continued to remain elevated at most locations. Palla was the only monitoring point with BOD within the acceptable range, at 3mg/L. Higher BOD indicates a greater load of organic pollutants requiring oxygen for decomposition. The DPCC collects samples manually from eight points, from Palla to Asgarpur. The August data also showed year-on-year improvement, with faecal coliform at Okhla declining from 54,000 MPN/100ml in August 2025 to 23,000 MPN/100ml this year. Despite the improvement, Asgarpur recorded the highest BOD, COD, phosphate and faecal coliform levels among the monitored locations.

Published by HT Digital Content Services with permission from Millennium Post.