NEW DELHI: A portion of a four-story building in India's financial capital collapsed in heavy monsoon rains, killing at least five people, authorities said.

National Disaster Management Authority official Vijayendra Dahiya said rescuers were using sensors and life detectors Tuesday to find five people still feared trapped in the debris of the building in the Sion area of Mumbai.

Another six people were injured when the building caved in Monday night.

Building collapses are common in India as builders try to cut corners by using substandard materials, and as multi-storied structures are built with inadequate supervision.

In April, 74 people were killed when an eight-story building being constructed illegally in the Mumbai suburb of Thane caved in. It was the worst building collapse in the country in decades.