The first underwater Metro is being constructed in Hooghly river. The project is awaiting clearance of 2.8 million USD from the Indian Railways. Highlights The Hooghly Metro is one of the oldest Metro in the country. It was started in 1984. The new under water tunnel will carry 20% of city’s population and will cross the river in less than a minute. Currently it takes 20 minutes in the ferry to cross the river and an hour to cross the Howrah bridge.