Three persons were injured, one of them critically, on Saturday when two buses collided on the busy Howrah Bridge which connects Kolkata to Howrah, Kolkata Police official said.
The collision took place in the middle of the bridge when two private buses bound for Kolkata were racing each other.
Three persons were brought out from one of the two buses, which was hit by the other on its right side and bore the brunt of the mishap, the official said.
One of the injured was rushed to a state-run hospital in Kolkata where his condition was stated to be extremely critical, the sources said.
The two other injured were taken to a nearby hospital.
The mishap threw traffic out of gear along one flank of the bridge for some time.