The Delhi government's pollution control body plans to penalise chief engineers of sewage treatment plants (STPs) that do not treat wastewater to prescribed standards, a major cause of high water pollution in the Yamuna river, after missing the deadline twice by the AAP government to clean the Yamuna to bathing standards.

Biological oxygen demand (BOD) and total suspended solids (TSS) in treated wastewater should be less than 10 milligrams per litre which is critical for cleaning the Delhi stretch of the Yamuna. The capital missed the December 2023 deadline to treat all the sewage generated to the prescribed standards.

The Delhi Jal Board (DJB) received a six-month extension but failed to meet the goal, according to monthly progress reports on the Yamuna river's rejuvenation sent to the Jal Shakti Ministry.

In March this year, Delhi set a target to increase its sewage treatment capacity to 814 million gallons a day, but this too was not achieved. Now, the DJB aims to reach a sewage treatment capacity of 922 MGD by December 2024 and 964.5 MGD by March 2025, according to the latest monthly progress report submitted to the Jal Shakti Ministry.

Any further delays could make it very difficult for the AAP led Delhi government to fulfil its promise of cleaning the Yamuna to bathing standards by February 2025. "It is almost certain that the 2025 deadline will also be missed, given the abysmal pace of rehabilitation and upgradation of the existing STPs to meet the standards and the construction of new ones," a former DJB official said.

However, the Delhi Pollution Control Committee (DPCC) wants the DJB to expedite their efforts. "We have been issuing reminders to the DJB, urging them to expedite the work and meet the deadlines. We even imposed penalties on the DJB. Now, we have decided to hold the chief engineers overseeing the upgrade of existing STPs and the construction of new STPs accountable," a senior environment department official said.

"We will impose personal penalties on the chief engineers responsible for specific sewage treatment plants if they do not comply with the standards," the official said.

Delhi generates 792 million gallons of sewage a day (MGD). The 37 sewage treatment plants (STPs) in the capital have a combined capacity of 667 MGD. Currently, these STPs utilise only 71 per cent of their installed capacity, treating 565 MGD of the 792 MGD of sewage, with the rest flowing untreated into the Yamuna river.