Pictures of the recent Chhath puja, with devotees waist deep in water in the Yamuna at Kalindi Kunj, raised eyebrows across the globe.
The women’s brightly hued attires were set off by the white around them — it appeared like they were worshipping the sun amid ice floes. A frozen river in Delhi? Well, experts now explain that the apocalyptic river scene was just the Yamuna covered in toxic froth.
Downstream of the Okhla barrage, this white surf has been visible for over a decade now. But river watchers and experts agree that the frothing hasn’t been checked, only increased in the last five years. River conservationist Manoj Mishra of Yamuna Jiye Abhiyan said: “Every year we see this phenomenon after the monsoons. As the temperature dips, the white bubbles created by detergent and phosphate components in the water become more stabilised and float on the surface.”
When the water is released from the Okhla barrage, the churning leaves the Yamuna surface covered with a foamy covering.
Similar phenomena in the lakes in Bengaluru and Hyderabad had left people aghast and scientists from NEERI (National Environmental Engineering Research Institute) had been summoned to find what was causing the whitening.
There is no one single reason for the thick foam bergs on the water surface. Ankit Srivastava, who is currently advising Delhi government on reviving water bodies, said that there are four primary causes of froth, adding, however, that until laboratory tests of the water from Kalindi Kunj were carried out, talking of the causes would be just speculating.
Srivastava explained that physical, biological and chemical factors were involved in the creation of froth. Untreated sewage flowing into the river might contain soap and detergent particles and when the water rushes down from the barrage height, soapy bubbles can be formed.
NEERI also noted that industrial run-offs contained surfactants constituted of chemicals used in industry as wetting agents, dispersants, defoamers, de-inkers, and in paint and protective coatings, pesticides, leather processing and plastic manufacturing. Srivastava said that in addition, biological factors are involved. Filamentous bacteria, for instance, produces organic compounds that act as surfactants.
Water experts in Delhi have consistently argued that common effluent treatment plant (CETP) aren’t adequate and the existing units are, in any case, not functioning properly. “STPs and CETPs are not functioning to their full capacity, and this is a complete failure,” Mishra said. In the meantime, thousands of industrial units operate from non-conforming areas without being challenged by civic authorities.
Dinesh Mohaniya, vice-chairman, Delhi Jal Board, chose to blame lack of regulation in Uttar Pradesh for the poor monitoring of water flowing into the Yamuna. “The drain from UP carries industrial effluents that pollutes the water,” he claimed. Mishra disagreed and said the contamination was primarily due to sewage from Delhi. He asserted, “This is completely an internal problem. The Shahdara drain is downstream and the froth can be seen much before that.”
While there may be various reasons for the icy look, one thing is certain: the froth on the river surface reflects the deadness of the water and indicates nil dissolved oxygen in it. The Yamuna monitoring committee has taken note of the photographs from Chhath Puja and has asked agencies — such as the central and state pollution panels and the industries department to respond.