4 min readNew DelhiMay 9, 2025 05:58 AM IST
First published on: May 9, 2025 at 05:58 AM IST
Lack of data on wastewater generation, direct discharge of faecal sludge from desludging tankers into rivers or drains in several locations, and mixing of treated and untreated sewage in the drains – these are some of key reasons for pollution in Yamuna, Delhi-based Centre for Science and Environment (CSE) stated in an assessment released on Thursday.
Sunita Narain, director general of CSE — a research and advocacy organisation — told mediapersons: “The focus of Yamuna Action Plan 2025 has been to build STPs (sewage treatment plants) so that domestic wastewater is intercepted and treated; improve the quality of treatment; build interceptor sewers to tap drains and divert sewage; lay sewage pipeline in unauthorised colonies and treat industrial waste in common effluent treatment plants…”
“All are good ideas… all needed. Then why is the Yamuna still polluted?” she asked.
She went on to say, “We do not know how much wastewater is generated by Delhi… as there is no clear data on Delhi’s population in the absence of a regular census or on the amount of unofficial water (groundwater and water supplied by tankers) that residents use… Without the data on wastewater, we must rework the plan.”
The report, titled ‘Yamuna: The Agenda for Cleaning the River’, noted: “…it is clear that cleaning the river will require more than money. It will need a plan, which recognises the reality that Delhi, like many other cities of India, is a city where the bulk of its people live in unauthorised areas, where sewage is not intercepted and therefore, not treated.”
Maintaining that there is a need to intercept the sewage and not release it back into the drains that carry untreated sewage, the report stated that it must also be ensured that the 22 drains opening to Yamuna are releasing only clean water.
As per the report, the focus of official actions, while “commendable”, has failed to address the issue of pollution because of concerns like – there is no dissolved oxygen in the river beginning from ISBT; Yamuna becoming polluted at Palla, an area located within a few km of the river entering Delhi; and no visible improvement in the river’s quality.
On how the Delhi government has been trying to curb pollution in Yamuna, the report noted a few measures – enhancement of sewage treatment capacity and its utilisation, tighter discharge norms, laying of sewage pipelines in unauthorised colonies, and controlling industrial pollution.
While the government has 28 “approved” industrial areas – effluents from 17 of these are treated in common effluent treatment plants – the report noted that “the quality of treatment is a matter of concern”. There is also a lack of clarity on the discharge locations post-treatment of these effluents, it added.
The CSE recommended a 5-point action agenda in order of priority:
– Ensure all faecal sludge is collected from non-sewered areas and treated. “The state does not have to invest in building and refurbishing costly sewage pipelines. The strategy for faecal sludge management through tankers is faster and more cost-effective,” Narain said, emphasising the need to ensure that all desludging tankers are registered and their movement monitored.
– Ensure that treated water is not discharged into drains, where it gets mixed with untreated wastewater.
– Ensure full utilisation of the treated wastewater so that they do not add to the pollution load. At present, only 331-473 MLD is reused, which is between 10-14% of the treated wastewater.
– Plan upgrade of the STPs based on the reuse of treated water plan and redesign the effluent standards.
– Rework plan for the two major drains — Najafgarh and Shahdara. Stating that these contribute to 84% of the pollution load in Yamuna, the report stressed that the government’s interceptor drain plan has not been working.
A polluted Yamuna. 
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