Building safety is a major issue in Mumbai, one of the world's most crowded cities

Prime Minister Narendra Modi today said he was anguished after a multi-storey building collapsed in Mumbai, killing ten and trapping at least 40 to 50 people under the debris.

The PM said the Maharashtra government, the National Disaster Response Force or NDRF and local authorities were working on rescue operations and assisting those in need.

"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 office of the prime minister tweeted, quoting him.

Around 11:40 am today, a 40-year-old four-storey building came down in south Mumbai's Dongri neighbourhood.

Eight people have been pulled out of the rubble so far with three large teams of the NDRF looking for survivors. The area, which has narrow lanes, is full of dilapidated buildings and had been flooded in heavy rain the past weeks.

The narrow lanes are also posing a major challenge for rescue workers to reach the site. Ambulances could not reach the site and had to be parked around 50 metres away.

The rescuers had to make hectic efforts to remove the mangled frames of furniture, including large sofas, from the rubble at the mishap site.

Scores of locals joined in the effort, forming a human chain to help in removing the debris brick by brick and picking up slabs of concrete to locate those buried.

Building safety is a major issue in Mumbai, one of the world's most crowded cities next to Dhaka in Bangladesh, according to the World Economic Forum.

In May, the civic agency Brihanmumbai Municipal Corporation or BMC in the country's financial and entertainment hub had identified 499 buildings as "dangerous"; it was 619 last year.

With inputs from Press Trust of India