A first in India, the two parallel 520-meter under the river tunnels will connect Salt Lake Sector V in Kolkata to the Howrah Maidan across the river, being elemental in Rs. 8,900 crore East West Metro Project by the end of July 2017. The work using a huge Tunnel boring Machine (TBM) has already begun on the bed of the Houghly River. The tunnels are being dug at a depth of 30 meters below the…