At least 10 people were killed and several others are trapped after a four-storey building collapsed in Dongri, Mumbai. (File Photo/AP)

The narrow lanes of Dongri area in south Mumbai where a building collapsed on Tuesday posed a major challenge for rescuers to approach the accident spot.

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

Twelve people were killed when the 'Kesarbaug' building, located in a bustling narrow lane in Tandel Street of Dongri area of south Mumbai, crashed, housing minister Radhakrishna Vikhe Patil said.

About 40 to 50 people are feared trapped under the debris, civic officials said.

Fire brigade, Mumbai Police and civic officials rushed to the site but the constricted lanes made it difficult to access the area, reduced to a mass of rubble, twisted concrete and broken wires.

In the midst of the melee, rescue workers toiled hard to retrieve the bodies and help the injured. Their efforts were hampered by the congestion and the narrow, cramped lanes.

Adding to the woes of rescuers, there was debris scattered everywhere and mesh of electric wires overhead, restricting their movement.

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.

Ambulances could not reach the site and had to be parked around 50 metres away.

Shahnawaz Kapde, a resident of Dongri area, said had the JCBs been able reached the accident site, the number of

casualties could have been contained.

"You can now understand what would have happened if it was raining. Thankfully, it is not raining, otherwise the rescue operation would have been almost impossible in such narrow lanes where rescuers can't even walk freely," he said.

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

"There is no open space here and honestly saying, we have never seen any open space. We have spent all of our lives in these dingy lanes," said another resident of the area.

"Thankfully, the debris being pulled out from the collapsed building's site is being dumped on a nearby road and immediately being removed from there," he added.