AAMAR METRO
KOLKATA
PRESS RELEASE
METRO TO REPLACE WATER COOL CHILLERS WITH AIR COOL CHILLERS TO CONSERVE GROUND WATER
KOLKATA, 07.08.2025
Rapid depletion of ground water reserve is a big concern for the world. With the advent of new technologies and progress of civilization, natural resources like water are being used more and more. Experts have already warned about the negative impact of such extensive use of ground water on mother nature. Ground water is part of hydrologic cycle. Ground water contributes to streams in most physiographic and climatic settings. It may cause land subsidence. It takes thousands of years to accumulate ground water. So, ground water depletion means we are extracting more than what is being replenished. In order to preserve precious ground water in a densely populated city like Kolkata, Metro Railway, Kolkata has taken a great initiative and is going to introduce modern alternative cooling system in Blue Line, India’s oldest Metro Corridor soon. For this, a tender has already been opened and evaluation work is going on. After evaluation, the work order will be placed. Work will commence from 2026 and will be completed by 2029.
In this initiative, out of 15 underground stations, the cooling system of 11 underground stations of Blue Line is earmarked for change from traditional water cool chiller to air cool chiller immediately. The familiar scene of cooling towers outside Metro stations is going to change. For this ambitious project, Central Government has already allotted ₹ 150 Cr. once this is implemented, Metro Railway will be able to save 18 crore litters of ground water consumption annually. This amount of ground water is required to run the water cool chillers for making Metro stations cool every year. once air cool chiller replaced the water cool chillers then this huge amount of water will be saved which in turn help to protect environment and water resources. A study on ground water resources has shown that at Borough VII and Borough VIII of Kolkata Municipal Corporation ground water level is declining at a rate of 30 cm per year in comparison to 11 cm per year in other boroughs. This initiative will help to arrest this trend and ground water level will be preserved for posterity. This initiative shall certainly reduce the rate of fall of ground water in Kolkata. Ground water depletion scenario is placed below:
District : Kolkata
Water table depth* (2021): 13.52
Average Water table depth (m): 11.40
Water table level (m) : -2.12
% decreased in 5 years average: (-19%)
In Blue Line there are 46 water cool chillers expiring its codal life at eleven different stations now. Out of which 30 water cool
chillers of eight stations are earmarked for immediate replacement, Remaining water cool chillers located at Netaji Bhawan, Jatin Das Park, Maidan and Mahatma Gandhi Road stations are earmarked for replacement by air cooled chillers and Metro Railway is committed to funding civil works required for creating space for air cooled chillers. Final decision will be taken after discussion with the experts and detailed design consultant. Water cooled chillers of Rabindra Sarobar, Kalighat, Chandni Chowk are expiring its codal life within three years. They will be also converted to air cooled chillers immediately before they expire its codal life.
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