Passengers will experience India's first underwater tunnel in a blink-and-you-miss-it moment as trains will transit the 520-metre length in only 45 seconds. The tunnel is being built under the Hooghly River in West Bengal at a cost of about Rs 120 crore as part of the East West Metro Corridor. The tunnel, which runs 33 metres below ground level and 13 metres below the riverbed, is the Indian equivalent of the London-Paris corridor of Eurostar. Piyush Goel, the minister, posted a video about it on his social media. The 520-meter tunnel is a section of Kolkata's East West Metro Corridor, which spans the river from Salt Lake Sector V, the city's IT sector, to Howrah Maidan, in the west.