An over 1,200-sq-ft chunk of Rajdanga Main Road, next to the site of a Rs 400-crore mall-stadium-highrise project, caved in on Tuesday night. The subsidence caused cracks in the walls of an adjacent five-storeyed building, which has also tilted forward.

Damage to the underground pipe has plunged the area into a water crisis.

The crack extends more than 80 feet in front of the Acropolis construction site, spread over more than a third of the 45-ft-wide Bypass connector, near Siemens.

Acropolis, being developed over 6.5 acres on the Kasba-Rajdanga ground, will house a 4,000-seat sports stadium, a 17-level business tower and a shopping mall with a four-screen multiplex. The plot was being excavated for the past few months to construct the three-level car park for 750 vehicles.

Mackintosh Burn, a state government undertaking, is executing the project for Merlin group and the Calcutta Metropolitan Development Authority (CMDA).

“We are living in constant fear as the first-floor wall has developed cracks and the building has tilted forward. There has been no structural damage but prompt action needs to be taken,” said Rajarshi Ray, a tenant of the damaged building.

Sujay Mukherjee, a structural engineer who also lives in the house, said the agency should have erected a wall to support the road before starting the excavation.

The road sprang cracks about five days ago, he added. “Water leaking from the underground pipe made the soil loose and caused the cave-in. The authorities turned a blind eye to the cracks. It could have been a disaster.”

While the civic body’s chief engineer (water supply) said the “compaction” of the road was not strong enough, the CEO of the CMDA dismissed the cave-in as a “small thing”.

Merlin Group managing director Sushil Mohta said “all the precautionary measures had been taken” but such mishaps were known to happen. “The civic authorities are taking appropriate measures.”

“A probe will determine whether the ongoing work needs to be reviewed,” said Nilmoni Dhar, the managing director of the executing agency. “I inspected the site. Sand filling is being carried out to stop another cave-in. We could not predict the mishap.”

He claimed that the tilt in the building was not caused by the subsidence.

The cave-in has caused resentment among residents, about 200 of whom are going without water. Some of them filed a police complaint.