At least 11 people were killed when a century-old, unauthorised four-storey residential building collapsed in south Mumbai’s Dongri on Tuesday, trapping over 40 people under the debris in an area whose narrow and congested lanes made rescue efforts difficult.

It was the second such collapse around Mumbai in less than 15 days. On July 2, a rain-triggered wall collapse had killed 24 people. Torrential rains that lash Mumbai during the monsoon often destabilise older or badly constructed structures and this has led to multiple collapses over the years.

“We don’t know exactly how many, but with the input provided by neighbours, we estimate more than 40 could be trapped,” said a civic official.

Maharashtra chief minister Devendra Fadnavis said the Kausarbaug building, located in a bustling narrow lane in Tandel Street, was around 100 years old and housed 10 to 15 families. It was not on the list of dilapidated buildings and had been given to a developer for redevelopment, the chief minister said.

Housing minister Radhakrishna Vikhe Patil had said earlier that 12 people had been killed in the 11.40am collapse.

According to a Brihanmumbai Municipal Corporation (BMC) mayor Vishwanath Mahadeshwar, the municipal commissioner will probe the building cave-in.

TV channels showed dramatic visuals of a child, wrapped in a cloth bundle, being carried out of the debris by rescue workers. The child is alive, officials said.

The BMC has opened a shelter at Imamwada Municipal Secondary Girls’ School for the residents of the building, a civic official said.

“A team of the National Disaster Response Force (NDRF) is reaching the spot. We are assuming that 10 to 12 families are still under the debris,” Mumbadevi MLA Amin Patel told reporters at the spot earlier in the day.

The building was unauthorised, officials of the Maharashtra Housing and Area Development Authority said, adding that it was not under its supervision.

Rescue operation at the site on Tuesday (PTI)

Legislator Bhai Jagtap said residents had complained to housing authorities about the old and dilapidated building and sought prompt measures.

Fire brigade, Mumbai police and civic officials rushed to the site but the constricted lanes made it difficult to access the building, reduced to a mass of rubble, twisted concrete and broken wires. A portion of the building is still standing after the collapse. A mesh of overhead electricity wires further hobbled the rescuers.

As the JCB machines could not enter the narrow lane leading to the building, neither could ambulances, the rescue workers had to remove the debris with their hands and carry the victims to the ambulances parked 50 metres away.

Scores of local residents joined the rescue bid, forming a human chain to help remove the debris brick by brick and picking up slabs of concrete to locate those buried.

The rescue work was further delayed as politicians, including ministers, legislators and Opposition leaders, rushed to the area and hundreds of onlookers crowded the spot.

Some residents of Dongri, one of the most densely populated areas of Mumbai and having several high-rise buildings, said that had the JCB machines been able to reach the accident site, more lives could have been saved.

Shahnawaz Kapde, a resident, said: “You can understand what would have happened had it been raining. Then, the rescue operation would have been almost impossible.”

The rescuers had to make their way by removing mangled frames of furniture, including large sofas, from the rubble.

A youngster was seen shouting out instructions over a megaphone to onlookers to clear the area so that the rescue operation could be carried out.

A resident of the building, Huma Sheikh, was seen waiting anxiously, teary eyed, for news of her mother, younger brother and niece, who are feared trapped in the debris. “I was leaving for office and realised I had forgotten my vehicle’s keys. I asked my mother for it. No sooner did she come to the window to throw it down that I saw the building cave in,” Huma said.

Congress leader Milind Deora demanded that the chief minister call a meeting to address frequent wall collapses. “This is unfortunately something that happens in Mumbai every year during monsoon. Walls collapse, there are potholes on roads where people die and young boys fall into manholes,” he said.

Prime Minister Narendra Modi expressed anguish over the deaths. “Collapse of a building in Mumbai’s Dongri is anguishing. My condolences to the families of those who lost their lives. I hope the injured recover soon. Maharashtra government, NDRF and local authorities are working on rescue operations & assisting those in need,” the Prime Minister’s Office tweeted, quoting Modi.