Work on a drainage pumping station at Gulshan Colony in Anandapur along EM Bypass was stalled by a group of men who allegedly attacked Kolkata Municipal Corporation workers at the site and damaged a KMC vehicle.

Calcutta Mayor Firhad Hakim criticised the attack on the workers. “If my men are attacked, it is equivalent to attacking me. I will ask police to take severe action,” Hakim said, reacting to the violence on Monday morning.

CCTV footage has emerged that shows a group of men running after another group and threatening to hit them with an iron rod and a sharp weapon.

“The drainage project is worth over ₹11 crore. Some history-sheeters have started to create disruptions,” said Ward 108 councillor Susanta Ghosh.

The police said they have received a complaint and were trying to arrest the accused men. No one was arrested till Monday night.