Kolkata Metro Railway will invest Rs 500 crore to modernise the four-decade-old air-conditioning and ventilation systems along the 16.9 km Rabindra Sarobar–Belgachhia stretch of the North-South (Blue) Line.

Covering 15 underground stations, the project will replace outdated environmental control systems (ECS) with advanced heating, ventilation, and air-conditioning (HVAC) units, ensuring cooler platforms, concourses, and tunnels. The overhaul also includes upgrading the twin tunnel ventilation systems for improved fire safety and evacuation efficiency, addressing today’s significantly higher ambient temperatures.

Existing centralised AC setups—comprising water-cooled chillers, towers, coils, and ducts, will be replaced with modern, energy-efficient systems. Metro sources noted that these upgrades will enhance passenger comfort and safety, especially during emergencies.

India’s first underground metro, launched in 1984 with a 3.4 km Esplanade–Bhowanipore stretch, the Blue Line now spans 30 km from Dakshineswar to Shaheed Khudiram. However, its southern terminal, Kavi Subhash, has been shut since July 28 after cracks appeared on supporting columns; truncated operations run to Dhalai Bridge. The tender process for the upgrade has begun, marking a significant milestone in modernising Kolkata’s oldest metro corridor.