India gets its first underwater metro

India’s first metro rail tunnel under a major stretch of water has been inaugurated by prime minister Narendra Modi, nearly four decades after metro services began in the country.

The tunnel connects twin cities Kolkata and Howrah, divided by the Hooghly River in the eastern state of West Bengal.

Kolkata was also the first city in India to have an operational metro system, in 1984.

When it fully opens to passenger services later this month, trains will pass under a 520-metre river stretch in just 45 seconds, making commuting easier for residents in both cities.

Metro rail services are now available in 15 cities across the country, with the Delhi Metro Rail Corporation covering an extensive 393km across the national capital region. In Delhi, elevated metro sections have been constructed over the Yamuna River, which could not have been possible in Kolkata due to lack of space.

“The underwater subway was a safer and more cost-effective option for the railways compared to building an elevated portion,” Kaushik Mitra, the chief public relations officer of the Eastern Railways, told The Independent.

“The underwater metro rail service will be opened to the public shortly,” he added.

The 4.8km stretch of the East-West Metro in West Bengal has been built at a cost of Rs 49.65bn (£470m), according to an official release. The deepest metro station would be at Howrah – 30m below the ground level.

The railways have constructed walkways on both sides of the tunnel, which are connected to ventilation shafts every 25 metres, Mr Mitra said. During an emergency, the passengers can be evacuated through these shafts.

Mr Modi took the first underwater metro ride, joined by several school students as he arrived in West Bengal to campaign for the upcoming general elections.

A video inside the rail coach showed Mr Modi interacting with the school children beside him. “This will speed up the communication system and reduce traffic congestion,” Mr Modi said, calling it a “proud moment” for the country.

Rail authorities have installed special illumination of the inner walls of the tunnels with blue lights to provide a feeling of being underwater.

Construction for the project began in 2017.