India, Dec. 4 -- Work has begun on Mumbai's deepest road tunnels, which will run 50 metres below ground at their lowest point. Chief minister Devendra Fadnavis on Tuesday inaugurated the launch of the tunnel boring machine (TBM) for one of the twin tunnels that will connect Orange Gate and Marine Drive in south Mumbai. The second TBM is expected to arrive within a fortnight, officials said.

The 9.96-km twin tunnels, expected to be ready by December 2028, will reach their maximum depth beneath Chhatrapati Shivaji Maharaj Terminus (CSMT). Estimated to cost Rs.8,056 crore, the project is expected to cut travel time between Orange Gate and Marine Drive by 15-20 minutes, according to officials.

According to officials from the Mumbai Metropol...