A vessel loaded with 165 containers partly capsized at Netaji Subhas Dock of the Kolkata port on Thursday, an official said.
No casualty was reported in the incident, though a number of containers have sunk. The matter is being investigated.
The vessel, M/V Marine Trust 1, was scheduled to travel to the Chittagong port in Bangladesh on Friday, said a spokesperson of the Syama Prasad Mookerjee Port (SMP), formerly Kolkata Port Trust.
"The vessel... suddenly capsized within 15 minutes at 10:40am. An enquiry into the incident has been ordered," SMP spokesperson Sanjoy Kumar Mukherjee said.
It was loaded with 120 twenty-feet containers and 45 forty-feet containers.
As the cargo ship tilted to one side, some of the containers have sunk.
"As seen from the berth level, 18 of the 20-feet containers directly went into the water while 10 of 40-feet containers are floating on the water surface. They were secured by tying ropes," Mukherjee said.
Measures are being undertaken to control the situation and minimise the loss to the cargo and the vessel.
However, except for the affected berth, operations remained normal on all other berths, SMP officials said.