A thick layer of white toxic foam was seen floating on the Yamuna River near Kalindi Kunj in southeast Delhi on Monday, prompting cleaning operations in the affected stretch, officials said.
Visuals from the area showed the river’s surface covered with white froth, bringing renewed attention to the pollution levels in the Yamuna, particularly ahead of the winter months — when the phenomenon frequently occurs.
The formation of foam is primarily associated with the discharge of untreated sewage and industrial effluents containing detergents and other chemical pollutants into the river.
The froth forms when soap-like substances, known as surfactants, present in detergents and other pollutants, mix with water and trap air bubbles. The churning of water near barrages, particularly where water falls from a height, further intensifies the process.
Lower temperatures during winter also make the bubbles more stable, allowing the foam to accumulate and remain on the river’s surface for longer periods, according to experts.
Apart from domestic sewage, industrial waste and discharges from washing activities along the river contribute to the problem. The resurfacing of foam comes days after a similar occurrence was reported at the Kalindi Kunj barrage on October 23, when a thick layer of froth covered the river stretch.
The DJB deploys chemical de-foaming agents during winter to control the accumulation of froth, particularly ahead of Chhath Puja, when devotees gather along the river for religious rituals typically around November every year.
It said it has been carrying out the cleaning exercise at Kalindi Kunj since 2022 and had set up two camps to store the remaining material from the previous year’s drive.
However, experts have maintained that such measures address the visible foam rather than the underlying pollution, with untreated sewage and industrial discharges continuing to affect the river’s water quality.