The incident happened at around 2PM when over ten motorbike-borne men came near an under-construction apartment at Bibibagan area and attacked a person named Shiekh Aslam, a senior police officer said.
They fired and two bullets hit Aslam's leg, he said adding a few bombs were also hurled by them at another gang, who on hearing the bullet firing rushed to the place.
Aslam was rushed to NRS hospital where his condition was stated to be stable.
The anti-rowdy section of Kolkata Police, which started a probe into the attack, said Aslam and one of the attackers Niwajuddin have "serious" criminal background.
This was probably a clash between groups involved in the construction of flats and there are allegations that the gangsters are involved in a racket selling a single flat to different customers, the police officer added.