A caller to the weekly Talk to Mayor programme complained on Saturday that a building that had been demolished by the Kolkata Municipal Corporation (KMC) was being erected again.

The mayor told KMC officials they should ensure the arrest of contractors and builders rebuilding an illegal structure, “merely catching the masons will not help”. Firhad Hakim asked officials to lodge FIRs in such cases.

The caller from Tollygunge told Hakim that despite the KMC pulling it down, the builder had started rebuilding the demolished portion.

The KMC used to drill holes, cut square or rectangular portions of floors and sometimes demolish parts of walls earlier when they went to pull down illegal buildings. More recently, they have started to pull down bigger portions of a floor with the hope that rebuilding the demolished portions will mean losses for the builder. Saturday’s call proved that builders have outsmarted the KMC.

In March, Metro reported about a six-storeyed structure in Bowbazar, where the builder had rebuilt demolished portions within two months. The civic body had to demolish the portions again.

“Lodge FIRs against such contractors and builders. They should be arrested. There is no use picking up some masons,” Hakim told officials of civic body.

He added: “There are laws that allow you to act against such builders. Use those sections of the law. Lodge FIRs against such contractors and builders.”

KMC engineers said rebuilding demolished portions happened primarily because builders felt they could grease the palms of civic officials and police officers, and because the demolition often left scope to rebuild illegal portions.

KMC’s lack of supervision also aids it.

Some KMC engineers said modern equipment and more funds should be made available so larger portions of an illegal building can be pulled down so it becomes impossible to rebuild the demolished portions without affecting the legal parts.

The KMC recently made it mandatory for all sub-assistant engineers of the KMC’s building department to upload pictures and provide detailed information about any illegal construction on a mobile app it has created. The sub-assistant engineers are supposed to go around in their wards and boroughs to spot illegal constructions.

A KMC engineer said there were 93 sub-assistant engineers for the KMC’s 144 wards.