Every winter, a thick layer of white froth forms on the Yamuna in Delhi. The Yamuna toxic foam looks like snow but it is actually a sign of heavy pollution. Experts say the foam appears because the river receives large amounts of sewage, detergent and chemical waste. Cold weather makes the problem even worse.
The foam forms when untreated or partly treated wastewater enters the river. This wastewater comes from households, factories and drains connected to the Yamuna. It contains detergents, oils and other chemicals. These chemicals act like soap and help bubbles to form. When the water in the river moves, these bubbles join together and create a thick sheet of foam. Because the river flow is weak in winter, the foam stays on the surface for a long time.
One major reason for the foam is the presence of surfactants, the chemicals found in soaps, cleaning agents and industrial liquids. Surfactants reduce the surface tension of water making it easier for bubbles to form. When thousands of litres of polluted water enter the Yamuna daily, the amount of surfactants increases. This makes the foam thicker and more stable.
A large part of the pollution comes from untreated sewage. Many drains in Delhi carry household waste directly into the river. Sewage contains organic waste that reacts with detergents and chemicals, increasing the frothing effect. Experts say the river receives more sewage than it can naturally clean.
Winter months create the perfect conditions for the foam to form. The river flow becomes weak, the cold temperature slows down the natural cleaning process. Pollutants build up instead of breaking down.Wind and water movement churn the polluted water, creating more bubbles.Because of these conditions, the foam rises, spreads and becomes more visible.
The foam is harmful for the skin and can cause irritation. People who live near the river say the smell becomes stronger in winter. The toxic chemicals can affect fish, plants and animals in and around the river. It also shows how polluted the water has become over the years.
Experts say the main reasons the foam returns every winter are: slow progress in treating sewage, high industrial waste in drains lack of proper enforcement on pollution control, more population and more wastewater entering the river
Until proper wastewater treatment increases and pollution controls are enforced, the winter foam will keep coming back.
Officials say they are working on new sewage treatment plants and upgrading old ones. They also plan to stop major drains from releasing untreated waste into the river. However, the results are slow and the river remains heavily polluted during winter.
The toxic foam on the Yamuna is not a natural event. It is the result of years of pollution, untreated sewage and chemical waste. Winter only makes the situation worse by slowing the river and allowing pollutants to build up. Cleaning the Yamuna fully will need long term planning, strong regulation and strict action against pollution.
