Heavy rains accompanied by strong winds ripped through Mumbai, the financial capital of India, on Monday, killing at least eight people, uprooting trees and causing power outages in many parts of the city, officials said.

The deaths were caused by a large billboard that toppled onto a crowd of people seeking shelter, a local official said.

Rescue workers from India’s national disaster force and local police officers were called in to help free dozens of people trapped in the rubble, in the eastern suburb of Ghatkopar. Video on social media showed the billboard shaking in the storm before falling.

One witness, Swapnil Khupte, said that when the rains and wind started becoming worse, he and his friends had taken shelter at a gas station near the billboard. When it collapsed, he said, many of the people trapped under it were women and children.

“All the cars, bikes and people that were there got stuck,” he told a local news agency. “We helped people get out and somehow manage to escape.”

Mumbai, home to more than 18 million people, sits on a peninsula surrounded by the sea. Like many other Indian cities, it is prone to severe flooding and rain-related accidents during the monsoon season, which runs from June until September.

In recent years, India has experienced a pattern of extreme weather, including record heat waves and heavy floods. The monsoon’s arrival last year has also caused damage and fatalities in many other parts of the country.

In all, 64 people were injured when the billboard toppled over on Monday were admitted to the hospital, said Bhushan Gagrani, an official of the Brihanmumbai Municipal Corporation, which runs Mumbai. One was listed as in critical condition.

The rains were followed by dust storms that some residents likened to a scene from a Hollywood movie. The authorities at the Mumbai airport said they had diverted more than a dozen inbound flights and suspended operations for more than an hour.

Though Monday’s rains bought some relief from the sweltering heats, many parts of the city were inundated, and there were long traffic jams.