Local people stand near a collapsed wall that killed at least 15 people in a slum settlement in Mumbai, India, following heavy monsoon rains on Tuesday. Photo: IC

At least 15 people were killed in Mumbai early Tuesday when a wall collapsed as torrential monsoon downpours brought chaos to the city.

Another 69 were injured when the structure came down around 2 am local time in a slum settlement, Tanaji Kamble, a disaster management spokesman for Mumbai's local authority, told AFP.

The tragedy came as the teeming coastal settlement of 20 million residents was lashed by heavy rains for a second consecutive day, bringing the city to a virtual standstill.

Authorities declared Tuesday a public holiday and advised all residents to stay indoors. Schools and colleges were closed while dozens of flights were cancelled and diverted from Mumbai's main airport.

The airport's main runway was shut after a SpiceJet plane overshot the runway shortly before midnight Monday, a spokesperson for the airport told AFP.

According to Skymet Weather, a private weather tracking agency, large swathes of Mumbai received around 350 millimeters of rain overnight into Tuesday morning.

The deluge left low-lying parts submerged in water. 

Around 1,000 people living close to the city's Mithi river were evacuated to higher ground as the river threatened to burst its banks, said Kamble, the disaster spokesman.

Train services on Mumbai's colonial-era rail network, a lifeline for the city's population, were reduced due to waterlogged tracks while motorists were seen pushing cars through flooded streets.

Rescuers were sifting through the wreckage of the wall that collapsed in a slum area in Mumbai's north, in the hope of finding more survivors trapped under rubble.

"Rescue operations are under way and more details are awaited. Besides, a team of fire brigade and local police also reached the spot and took control of the situation," a National Disaster Response Force official told the Press Trust of India news agency.

Mumbai's streets regularly flood during the monsoon, which runs from June until September or October, and which provides India with most of its annual rainfall.

In 2005, 950 millimeters of rain fell on the coastal metropolis in just 24 hours, killing more than 500 people.