Mishap tied to TBM hitting acquifer. 

The seal of a vital component of a tunnel boring machine of Kolkata East-West Metro gave way because of water pressure, leading to flooding of the tunnel in Bowbazar, engineers involved in the project said on Monday.

https://www.telegraphindia.com/states/west-bengal/water-tore-east-west-metro-tunnel-boring-machine-seal-engineers/cid/1702154

For background info read:

https://tunnelcontact.com/discussion/view/3696/india-homes-emptied-after-building-cracks-and-collapses-as-a-result-of-kolkatas-east-west-metro-tunnel-tbm-boring