People on river using a UV254 Analyzer (Dip-probe) to measure TOC, BOD, COD, DOC.

Mapping pollution
hotspots in Yamuna

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he Yamuna was considered a nurturing and life-enhancing goddess in the past. Legend has it that bathing in the sacred waters of the Yamuna, the sister of Yama, the god of death, frees one from the ordeal of death. The 1376-km river is a tributary of the Ganga and originates in the Yamunotri glacier in the lower Himalayas. It passes through several states in north India including Uttarakhand, Haryana, Uttar Pradesh and Delhi where the river was once its lifeline. Its water has been diverted about 200 km upstream of Delhi at Hathnikund barrage through the western and eastern Yamuna canals for irrigated agriculture while wastes from 50,000 industries and sewage from eight million people tear the natural system asunder. At Delhi’s Nigambodh ghat located on the banks of the Yamuna, one can see a series of bathing and ceremonial stepped piers leading to the waters of the river. River enthusiasts, activists and researchers have assembled there for a curated walk along the Yamuna and a boat ride with “sensors”. The river has been abused so much over time that it symbolises death in its 22-km stretch through Delhi today. “It is mid-April, and we are lucky that the river has not been reduced to a sludgy stretch, which it normally is at this time of the year,” says Himank Sharma, who has been working on the Water-to-Cloud project on the Yamuna.

The dissolved oxygen levels or the amount of oxygen dissolved in water in this stretch has severely depleted due to high levels of organic content in the water. It ought to be a minimum of five mg/litre, but there is nearly no dissolved oxygen (DO) in any stretch of Yamuna downstream of Wazirabad to Okhla barrage. The performance of the sewage treatment plants has been dismal and the biochemical oxygen demand (BOD) or the amount of dissolved oxygen needed for microorganisms to breakdown the organic matter in water has not met the standard of being upto three mg/litre. This indicator of water pollution is very high. Total coliform and faecal coliform, which are crucial parameters to gauge the biological contaminants present in water, too show very high values.