Levels of fecal coliform (microbes from human and animal excreta) is above desirable limits in all points tested in the Yamuna in Delhi, except for Palla where the river enters the Capital, as per a Delhi government report.
The report submitted to the Union Ministry of Jal Sakti also stated that in the absence of a “minimum environmental flow” (flow of water) of the Yamuna in Delhi, it is very difficult to achieve even bathing quality standards of the river water.
“Minimum environmental flow for the dilution of the polluted water in the Yamuna in Delhi is required to meet the desired water quality levels in the river for bathing purpose i.e. BOD<3 mg/l and DO>5 mg/l,” the report read.
For bathing in a river, the desirable level of fecal coliform in the water is 500 MPN/100 ml or lesser, as per the Central Pollution Control Board.
But the level was as high as 1,40,000 MPN/100 ml — 280 times the desired level — at Okhla Barrage, a point along the river in Delhi, as per the report.
Over 80% polluted
The 22 km stretch of Yamuna from Wazirabad to Okhla in Delhi, which is less than 2% of the river length, accounts for about 80% of the pollution load in the river.
According to the International Union for Conservation of Nature, an environmental flow is the water provided within a river, wetland or coastal zone to maintain ecosystems and their benefits where there are competing water uses and where flows are regulated.