Despite substantial government investment and an expanding sewage infrastructure, the Yamuna remains one of India’s most polluted rivers. A new report from the Delhi-based think tank Centre for Science and Environment (CSE) said it's time to fundamentally shift how Delhi tackles the problem. The think tank has released a detailed assessment and five-point action plan urging policymakers to reset priorities and adopt a more targeted, data-driven approach.
Titled Yamuna: The Agenda for Cleaning the River, the CSE report highlights the paradox at the heart of Delhi’s river-cleaning efforts. Between 2017 and 2022, the Delhi government spent more than Rs 6,856 crore to clean the Yamuna. The city now boasts 37 sewage treatment plants (STPs), claiming the capacity to handle 84 per cent of its wastewater, with nearly 80 per cent of households connected to the sewer network. Yet, the 22-kilometre stretch of the Yamuna that runs through Delhi remains biologically dead.
Sunita Narain, director-general of CSE, said at the press briefing that while the ongoing efforts are laudable, they have not delivered the desired outcome. “The problem of cleaning the Yamuna is not a new one; huge amounts of money have been spent over the years, plans have been initiated and carried out. The agenda for cleaning the river is critical as a ‘dead Yamuna’ is not just a matter of shame for the city and for us – it also adds to the burden of providing clean water to Delhi as well as to the cities downstream.”
“We must realise that cleaning the Yamuna will require much more than money. It will need a reworked plan which will guide us towards thinking and acting differently.”
The CSE report identified three core weaknesses in the current strategy.
Lack of data on wastewater generation: The report notes that Delhi does not have accurate figures on how much wastewater it generates, largely due to outdated population data and the informal use of water through borewells and private tankers. Without this information, it’s difficult to design a system that matches actual waste output.
Unregulated desludging operations: Large areas of Delhi are not connected to sewers and rely on desludging tankers to remove faecal waste. However, these tankers often dump untreated sludge into drains or directly into the river. There is currently no comprehensive regulation or tracking mechanism to ensure that sludge is transported to treatment plants.
Mixing of treated and untreated wastewater: Even in areas with treatment facilities, the treated effluent is often released into open drains, which are already contaminated with untreated sewage. This negates much of the benefit of the treatment process.
The report acknowledges several important initiatives. The expansion of sewage treatment capacity, new discharge standards, and the laying of over 1,000 sewer lines in unauthorised colonies are key milestones. The Delhi government’s Interceptor Sewer Project aims to divert 1,000 million litres per day of sewage from drains to treatment plants. Additionally, tighter norms for treated effluent — 10 mg/l of Biochemical Oxygen Demand (BOD), compared to the national standard of 30 mg/l — reflect an effort to push for cleaner discharge.
Yet these measures are not proving adequate. According to a 2024 Delhi Pollution Control Committee (DPCC) report, 23 of the 37 STPs are failing to meet the stricter effluent standards. Moreover, the water quality downstream of Wazirabad deteriorates so quickly that the BOD level drops to zero at the ISBT bridge — a sign that the river has lost all its oxygen and ability to sustain life.
The CSE proposes a five-pronged strategy that shifts the focus from infrastructure expansion to better governance and planning.
Bring faecal sludge into the treatment chain: Instead of building costly new pipelines, authorities should regulate and track desludging tankers, ensuring all faecal sludge from non-sewered areas is treated.
Stop discharging treated water into dirty drains: STPs must rethink their discharge plans to prevent treated effluent from being contaminated downstream.
Maximise reuse of treated water: Only 10-14 per cent of treated wastewater is currently reused. CSE recommends every STP have a clear plan for recycling its output.
Upgrade STPs with reuse in mind: Future investments should prioritise technologies that support water reuse rather than merely meeting discharge standards.
Target the worst drains: The Najafgarh and Shahdara drains alone contribute 84 per cent of Delhi’s Yamuna pollution. Current interception strategies are failing here and need to be overhauled.
The full report is available on the CSE website in Hindi and English.