A portion of an old house on Beleghata Main Road collapsed early on Thursday while it was raining heavily, killing a 70-year-old woman and injuring her son.

Around 4.30am, the front portion of the house’s roof that is supported by iron beams and mounted on old pillars came crashing down, police said.

Pratima Saha and her son Rajesh were trapped in the debris. Some residents of the area alerted Beleghata police station and a team of cops and Disaster Management Group personnel reached and rescued the two.

They were taken to NRS Medical College and Hospital where Saha was declared dead. Rajesh, who had received severe injuries on the head and arms, was admitted to the orthopaedic ward.

“The house is nearly 150 years old. The Calcutta Municipal Corporation has served several notices to the family asking them to pull down the structure,” a civic official said. “Even a board declaring the house to be a dangerous building had been put up.”

Rajesh lived in the house with his mother, wife and son. His wife had recently gone to her father’s place. His son was asleep in a room at the rear side of the house when the front portion collapsed.

“The family members will be asked to vacate the house as soon as they can because we are not sure about the structural stability of the remaining part,” an officer said.

Firhad Hakim, the chairman of the CMC’s board of administrators, called up senior officials of the civic body early in the morning and instructed them to help the police in removing the debris.