Most locations along the Yamuna in Delhi still fail in meeting water quality standards, 11 months after a high-level committee was constituted by the National Green Tribunal (NGT) to look into the rejuvenation of the river. According to data submitted by the Central Pollution Control Board (CPCB) to the NGT, out of seven locations along the Delhi stretch of the river, water quality at only two locations (Palla and Wazirabad, near where the river enters Delhi) meet water quality criteria for outdoor bathing. Dissolved oxygen — which is the quantity of oxygen dissolved in water, allowing the survival of aquatic life — is nil at four locations downstream of Wazirabad, the report submitted by the CPCB noted. “The reasons for deterioration of water quality of river Yamuna downstream of Wazirabad is due to non-availability of fresh water and discharge of partially treated wastewater from 18 drains into river Yamuna,” it added. In October, while hearing a matter concerning pollution in the river, the NGT had asked the CPCB to verify the facts and figures disclosed in the reports placed on record by the states and authorities, and “file a comprehensive report reflecting the correct position.” Of the 24 drains in Delhi identified to be discharging wastewater into the river, seven have been tapped, which means that they carry their water to a treatment facility, so far, according to the report. As for three of the city’s large drains, the Najafgarh drain, the Supplementary drain and the Shahdara drain, work on intercepting the sub-drains that meet them is underway, as per the report. Compared to data from the Delhi Pollution Control Committee (DPCC) on water quality of the Yamuna in October last year, biochemical oxygen demand (BOD), which is the oxygen needed for organic waste to decompose, is lower at all seven locations this October. At ITO, for instance, the BOD in October last year was 53 mg/litre, according to the DPCC while it was 31 mg/litre in October this year, as per the CPCB’s report.
