NEW DELHI: The latest monthly assessment of the Yamuna river at most places in the national capital fails to meet basic water quality standards, the Delhi Pollution Control Committee (DPCC) said in a report. On May 1, water samples were collected from eight monitoring points including -- Palla, Wazirabad, ITO, Nizamuddin, Okhla, and Asgarpur -- which showed high concentrations of biochemical oxygen demand (BOD), chemical oxygen demand (COD) and fecal coliform, it said.
According to the report, the higher concentration of BOD, COD and fecal coliform indicate severe organic and bacterial contamination.
The committee said BOD which reflects the amount of oxygen needed by bacteria to break down organic matter in water, were recorded at extremely high levels ranging from 4.0 milligrams per litre at Palla to 64.0 milligrams per litre downstream at Okhla.
The permissible BOD level for Class ‘C’ water (designated for outdoor bathing) is only 3 milligrams per litre.
It said that COD levels, which indicate the presence of oxidisable pollutants, peaked at 171 milligrams per litre at ITO Bridge -- above the acceptable limit of 250 milligrams per litre for inland surface waters.
Fecal coliform levels at ITO Bridge reached 92,000 MPN/100ml—around 37 times the safe limit—indicating severe sewage contamination. High coliform and ammonical nitrogen levels were also recorded downstream. Nizamuddin Bridge showed 5.75 mg/litre of ammonical nitrogen, well above the 1 mg/litre threshold. Palla, upstream in north Delhi, remained the only relatively cleaner site.