At least six labourers were killed after the compound wall of a college in Ambegaon locality of Pune collapsed in the early hours of Tuesday, The Indian Express reported. A portion of the wall of Sinhgad College collapsed on the adjacent makeshift tin sheds as heavy rain continued to lash the city.

The labourers hailed from Chhattisgarh and Madhya Pradesh, The Hindu reported. A first information report has been registered against the builder, land owner, contractor and officials of Sinhgad College after the incident, according to ANI.

Fifteen labourers were trapped under the debris, while local residents and a fire brigade team rescued nine. A team from the National Disaster Response Force was rushed to the spot for rescue operations.

“This is a manmade mistake as basic rules were not followed in the construction of the wall,” The Indian Express quoted District Collector Naval Kishore Ram as saying. “Also, the labour camps alongside the walls should not be constructed.”

Ram also said that the heavy rain caused the trees and the wall of the institute to crash on the tin sheds. “The main issue here is the hazardous position of the labourers’ quarters,” The Hindu quoted him as saying. “It appears as if this threat [of a wall collapse] was not assessed by the builders when they set up camps for the workers near the compound wall.” He further added that nearly 30 labourers, working on a residential block, were living in the sheds.

Four of the injured were being treated at the Sassoon General Hospital, while police were trying to ascertain their identities.

Pune Mayor Mukta Tilak said that the compound walls of the institute were a threat to life. “There are dilapidated buildings in the central part of Pune and people should be shifted at a safe location,” she said. “The PMC administration has to take necessary actions without delay.”

The incident came three days after 15 people were killed following a similar wall collapse on adjacent slums in Kondhwa locality of the city amid heavy rain. The slums housed labourers working at a construction site nearby. Teams from the National Disaster Response Force and the fire department rescued two men and a woman, who were taken to hospital with severe injuries.