Four persons were injured after portions of the third-floor cornice of a building off Park Street came crashing down on Monday afternoon. The five-storey building, Jaiswal Mansion, stands on Rafi Ahmed Kidwai Road.

“Three of the injured were admitted to SSKM Hospital with head injuries and discharged later in the day,” said an officer of Park Street police station. He said the police had cordoned off the footpath where the 2ftx1.5ft slab fell and asked the civic body to pull down portions of the cornice that were still hanging.

Two of the injured were identified as street food vendors Shankar Singh, 45 and Uttam Halder, 22. A customer, Barun Chakraborty, 30, and a passerby, Bipul Hazra, 24, were also injured.

“I was serving food when I heard a loud thud and a slab came crashing down. I lost consciousness and woke up in hospital with pain on the back of my head,” said Shankar.

A probe revealed there had been similar mishaps at the 54-year-old building earlier. “Portions of the wall and cornice had fallen off on at least three occasions in the past few years,” said an officer.

“We had razed the illegal portions of the building. Now if there is a cave-in, criminal proceedings should be started against the building owner,” said Gorachand Mondol, the director-general (buildings) of the CMC.

Jaiswal Mansion houses residential flats and offices and the cave-in has left those working in the building jittery. A private bank and its ATM situated on the ground floor remained shut till the evening.

“I was about to enter the building when I saw the cornice falling and moved away in the nick of time. It was probably the luckiest escape of my life,” said Dipankar Ghosh, a senior official of an RBI office on Royd Street.

The CMC official said there were more than 2.5 lakh such illegal buildings in Calcutta, many of them in Jadavpur, Kidderpore, Kasba and Behala.