At least 37 people were killed as walls collapsed in different cities after heavy rains hit India's Maharashtra state, according to the reports.

Among the deaths, 21 people were killed as a wall collapsed on shanties after heavy rains hit India's financial capital Mumbai on Tuesday.

"Rescue work is still going on," the official added. "So far, we have rescued more than a dozen people."

A second straight day of heavy rainfall in Mumbai also disrupted rail and air traffic and forcing authorities to declare a public holiday.