22-km stretch accounts for 80% pollution load in Yamuna

Najafgarh and Shahdara drains, the first near Wazirabad barrage and the latter near Okhla barrage, contribute to nearly 80 per cent of pollution in the Yamuna, according to the Centre for Science and Environment (CSE).

The 22-km stretch of the Yamuna in Delhi, barely two per cent of the total length of the river basin, contributes over 80 per cent of the pollution load in the entire river. There is no water in the river for almost nine months in a year and what flows in it is just sewage and waste from Delhi’s 22 drains. As per the report, there are three prominent reasons for pollution in the river. The first is the lack of data on wastewater generation.

The government had launched an Interceptor Scheme, under which 108 drains, with outfalls into Najafgarh, Supplementary and Shahdara, were to be ‘trapped’, intercepted and diverted for treatment.

Under this project, there were six packages that were planned in terms where it would be intercepted and where the sewage would be treated. According to the 2019 report of the River Rejuvenation Committee, out of the 900 treated MLD that was planned to be intercepted, roughly half had been completed by 2019. By 2024, it was claimed that 800 MLD is now being intercepted, but it is not clear how much of this is from the six packages for the key drains. This is also when pollution load has continued to increase in both Najafgarh and Shahdara, which clearly suggests that there is an urgent need to review and rework the plan.

Second, vast areas in Delhi depend on desludging tankers for removing their excreta and these tankers then discharge into the river or into drains. The current plan does not prioritise 100 per cent interception from tankers and on ensuring that this is then taken to STPs for treatment and reuse.

The third reason is the mixing of treated and untreated sewage in Delhi’s drains. Delhi has 22 drains that are supposed to carry treated, clean water back into the Yamuna. But untreated sewage also flows into these drains through unsewered colonies or tankers that transport faecal sludge and wastewater. As a result, the entire effort of treating the wastewater is negated.

The report also focused on five-point solutions which include focus on non-sewered faecal sludge collection and treatment, ensuring that treated water is not discharged into drains, where it is mixed with untreated wastewater.

Finally, the government should ensure full utilisation of treated wastewater and bio-solid so that this does not add to the pollution load; focus on every drain that outfalls into the river, not just the four-five major drains; and rejuvenation of water bodies with reuse of treated water and the recharge of groundwater.