A large number of houses and streets in Bengaluru were inundated on Sunday after the boundary wall of Hulimavu lake off Bannerghatta Road collapsed, The Times of India reported. More than 1,000 families were reportedly affected and over 300 cars had submerged.

Preliminary probe revealed that the breach occurred when the contractor allegedly used an earthmover near the bund to lay a pipe and failed to take precautionary measures.

The breach was reported around afternoon, following which officials from the Bruhat Bengaluru Mahanagara Palike, the city’s civic body, and Fire and Emergency Services and Quick Response Teams rushed to the area. The National Disaster Response Force personnel were also sent.

BBMP officials said some areas were flooded to a height of two-to-five feet, The Indian Express reported. “The Quick Response Team of Karnataka civil defence corps was called in first,” officials said. “Rescue operations began in the afternoon itself with rescue boats, de-watering floating pumps, life jackets, floating stretchers, first aid kits, and other necessary equipment.”

The civic body said 193 people were evacuated to safety. It took the personnel hours to contain the breach. Pumps were used to flush out water from basements of residential complexes and truckloads of mud was used to cover the breached bund.

Arekere Corporator Bhagyalakshmi Murali said a contractor had taken up developmental activities around the lake for the past two days and tried to drain it by making a small hole in the bund. “The contractor had said he would place sandbags so that the the water would not enter residential areas and flow towards storm drain,” she added. “However, he disappeared after the breach.”

BBMP Commissioner BH Anil Kumar said they were investigating the cause of the breach. “Three theories are doing the rounds: A private contractor had taken up work without authorization; fishermen damaged the bund; and BDA was at work,” he said. “We’ve filed an FIR with the local police and want police to probe the breach.”

Kumar tweeted that 80% of work to build a temporary bund and stop water flow had been completed with the help of BMRCL trucks and earthmovers.

The affected families were shifted to newly opened rehabilitation centres.

Several residents took to Twitter to highlight the problem and demanded legal action against the perpetrators.