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Gangetic Dolphins Return: A Triumph for Ganga's Water Quality
10 Feb
Summary
- Dolphin sightings indicate significant improvement in river water quality.
- 32 sewage treatment plants made operational, reducing pollution.
- Biochemical Oxygen Demand levels have dropped significantly since 2018.
Gangetic dolphins are being sighted more frequently across various stretches of West Bengal's rivers, indicating a significant improvement in water quality. Officials attribute this positive development to the ongoing efforts under the State Mission for Clean Ganga.
Over the past five years, the operationalization of 32 sewage treatment plants (STPs) has drastically reduced pollution. These STPs collectively treat an additional 554 million litres per day (MLD) of wastewater. As a result, the biochemical oxygen demand (BOD) of the river's entire Ganga stretch has fallen below 3 mg/L, a considerable decrease from the 12 mg/L recorded in 2018.
Further enhancing the river's health, four STPs were put under trial run in April 2025 and are now functional. These are located in Maheshtala, Raghunathganj, Jangipur, and North Barrackpore. Consequently, the entire Hooghly River stretch, from Farakka to Diamond Harbour, has been upgraded to the least polluted category.
To combat faecal coliform levels, septage is now being co-treated at functional STPs. A new 125 KLD STP in Baidyabati, Hooghly, is treating septage from six nearby municipalities, aiming to further reduce contamination. The rising dolphin population is also fostering tourism and improving local livelihoods.
