Untreated sewage, detergents behind recurring toxic froth in Yamuna: Govt tells RS

New Delhi, Mar 9 (PTI) Untreated or partially treated sewage containing detergents is a key reason behind the recurring toxic froth in the Yamuna river, the Rajya Sabha was informed on Monday.

Replying to a question, Minister of State for Jal Shakti Raj Bhushan Choudhary said, Central Pollution Control Board (CPCB) carried out monitoring on river Yamuna at Kalindi Kunj, downstream of Okhla barrage in view of the froth/foam formation in river Yamuna in the year 2022-2024.

"The causal link for the froth formation is due to the sudden fall of water from the barrage; agitation of foaming agents present in the wastewater forming foam which floats on the surface of river Yamuna," he said.

"Surfactants in detergents are the main foaming agents present in the untreated sewage or partially treated sewage," the minister said.

He said that the 'Study on Yamuna Frothing in Delhi', conducted by Department of Environment, Government of NCT of Delhi through The Energy and Resources Institute (TERI), found that the trigger of the event is mainly the poor water quality of the river, which results from various factors such as effluent containing high ammonia and phosphate, released from anionic surfactants.

The government said the main reasons for pollution in the Yamuna in Delhi include discharge of untreated or partially treated sewage into river Yamuna, absence of common effluent treatment plants (CETPs) in some approved industrial areas and delay in completion of new projects and rehabilitation and upgradation of sewage treatment projects.

As informed by the Delhi Pollution Control Committee (DPCC), the gap in sewage treatment in June 2025 was 645.55 million litres per day (MLD), the minister said.

Under the Namami Gange Programme in the state of Delhi, a total of 11 projects have been sanctioned at a cost of Rs 2,506 crores for the creation of 1,273 million litres per day (MLD) of sewage treatment capacity, he said.

Out of these, nine projects, with a combined treatment capacity of 1,268 MLD, have been completed, he added.

As per the Delhi Jal Board (DJB), 37 sewage treatment plants (STPs) are operational in Delhi. Out of these, 28 STPs, with a combined treatment capacity of 3,338 MLD, have been upgraded to meet the latest CPCB/DPCC standards, while the remaining nine are functioning on old norms and design parameters, the minister added.

Thirteen CETPs have been provided with a capacity of 212.3 MLD, for the treatment of waste water generated from industrial areas to control water pollution from industries in Delhi, the minister noted. PTI KSH PRK