New Delhi: The Yamuna River recorded its highest pollution levels in November 2023 since December 2020, with faecal coliform counts escalating significantly. According to the Delhi Pollution Control Committee (DPCC), the faecal coliform count reached 79,00,000 most probable number per 100 milliliters (MPN/100ml). This marks a sharp increase from 3,20,000 in 2023 and 6,80,000 in 2021, a TOI report stated.
The river’s biochemical oxygen demand (BOD), a measure of organic pollution, also deteriorated in November, indicating a worsening pollution load compared to October.
Faecal Pollution Exceeds Standards
Faecal coliform levels in the Yamuna, which reflect untreated sewage contamination, were alarmingly higher than permissible limits. For water to be considered healthy, faecal coliform should not exceed 2,500 units, with an ideal limit of 500 units. In stark contrast, the faecal coliform levels in December 2020 had reached 1,20,00,00,000 MPN/100ml.
Frothing and Other Parameters Show High Contamination
Visible frothing, caused by pollutants such as surfactants and phosphates, has been reported in several stretches of the river since September. Other indicators like dissolved oxygen (DO) and BOD were also far from acceptable. While DO, a measure of the water’s ability to sustain life, fell to nil in heavily polluted stretches, BOD values spiked far above the permissible limit of 5 mg/l.
At Palla, where the river enters Delhi, the DO level was 6.1 mg/l, and faecal coliform levels were within limits at 1,100 units. However, by the time it reached the ISBT bridge, DO dropped to zero, and faecal coliform levels soared to 490,000 units.
Monsoon Impact and Persistent Issues
While surplus monsoon rains earlier in the year brought additional upstream water and improved DO levels, they failed to dilute other pollutants. SK Sarkar, a distinguished fellow at TERI, emphasized, “Unless there is 100% sewage treatment in Delhi, the Yamuna will remain polluted. Most pollution comes from untreated sewage flowing into the river through various drains.”
Sewage Treatment and Future Plans
The Delhi Jal Board (DJB) stated that the city generates 792 million gallons of sewage daily (MGD), of which 650 MGD is treated. Despite having an installed capacity of 712 MGD, untreated sewage continues to flow into the river due to incomplete coverage and inefficiencies at sewage treatment plants (STPs).
DJB has assured the National Green Tribunal that most STPs will meet treatment standards by March 2026. “Contamination must be treated at the source. More rigorous monitoring and public awareness are essential to address the issue,” Sarkar added.
Experts and authorities agree that complete sewage treatment is critical to restoring the Yamuna’s health. Without immediate and sustained efforts, the river’s pollution levels will continue to pose serious environmental and public health challenges.
