Drones to track river pollution along 120 km stretch of Hooghly
Times of India | 20 January 2026
Kolkata: For the first time, the State Mission for Clean Ganga (SMCG), West Bengal, with the technical assistance of the Kolkata Metropolitan Development Authority (KMDA), will conduct a drone-based survey to identify and map all outfalls and drains, covering a stretch of about 120 km along both sides of the Hooghly from Kalyani in Nadia to Diamond Harbour in South 24 Parganas for pollution abatement work.
Officials said the objective of the survey will be to ensure that no drain discharging wastewater into the Hooghly river remains untreated. "This exercise will facilitate the preparation of wastewater treatment projects in the future and help explore the feasibility of tapping identified drains with existing sewerage treatment plants," said a KMDA official.
Officials said the survey will be carried out using advanced drone survey techniques. About 100 m of width along both riverbanks (80 m terrestrial area and 20 m aquatic area) will be covered under the survey. The authorities will engage an agency that will identify all outfall drains discharging into the Hooghly, along with their latitude, longitude, and cross-sectional dimensions, with the help of the drone survey.
Officials said the identified drains will be superimposed with drains already identified by the Central Pollution Control Board (CPCB), as well as additional drains not covered by the CPCB. "KMDA will provide a list of approximately 400 drains, which will be superimposed with the outfalls identified through the drone survey," said an official, adding that previously there were only physical surveys of the areas along the riverside.
Officials said that once a detail mapping of the drainage outlets is done, the authorities would be able to draw plans for effective reuse of treated waste water generated from the sewerage treatment plants. "Waste water is also falling into the Hooghly river. Plans could be drawn for effectively using waste water for pisciculture, gardening or road washing purposes," said an official.
KMDA officials said they were periodically working on setting up new sewerage treatment plants in riverside areas, and the plan is to fully prevent any sewerage or drainage water from falling into the river.
The authorities also planned to prepare a master plan for pollution abatement in the Ganga and its tributary basin in the Kolkata Metropolitan Area for the projected population in 2042, with a focus on liquid waste management, interception and diversion of sewerage network connections, and bridging the gap in sewage and septage treatment capacity around river-centric cities and towns.