While sewage discharged into the river accounts for much of the Yamuna’s pollution, the froth on its surface comes from an entirely different source —illegal jeans dyeing units. These mostly operate without a ‘consent to operate’ certificate or have an effluent treatment plant in place. Water discharged by such units, therefore, is high in ammonia and phosphates compounds, which are not only toxic for aquatic life, but also the cause of the thick foam on the river water.

Following a plea in National Green Tribunal in 2019, Delhi Pollution Control Committee was asked to act against all illegal jeans dyeing and washing units in the city. Till date, 155 have been issued closure orders after recent detection of these polluting units in the Khayala, Bawana, Narela and the Badli industrial areas to add to those found in the past two years in Sarita Vihar, Mayapuri and Nangli Sakrawat.

A DPCC official said that so far, the illegal units, most without effluent treatment plants, had been fined Rs 3.08 crores. More than six units were closed and others served notices. “More closure notices will be served in the next few months,” declared the official.

Varun Gulati, the petitioner in the NGT case who also took part in the crackdown at Khayala, says groundwater is the first to suffer in areas at some distance from the Yamuna. “Drains where these units discharge waste are frothing and the dyes turn the colour of the water to red or pink,” said Gulati. “Each day, hundreds of thousands of litres are being discharged into the Yamuna. This needs to be stopped to improve the river and ground water quality.”

Bhim Singh Rawat, a Yamuna activist and member of the South Asia Network on Dams, Rivers and People (SANDRP), pointed out that while organic pollution through sewage could still be diluted by increasing the water flow, toxic dyes and chemicals not only killed good bacteria in the river water but also affected the Yamuna’s self-cleaning’ property. “If there is organic waste, the river has the capacity to clean itself,” Rawat said. “But this is not possible with chemical pollution. The dyes cannot be washed away and do not break down naturally, causing harm both to aquatic life and humans.”

Delhi’s animal husbandry department recently banned fishing at two highly polluted points in the Yamuna where the fish were likely to be toxic. DPCC too banned the sale of soaps and detergents that did not meet the Bureau of Indian Standards norms to check froth formation.