MUMBAI -- At least 14 people died and 75 others were injured after a billboard bigger than an Olympic swimming pool fell on them during a thunderstorm in India's financial capital Mumbai, authorities said on Tuesday, with dozens still feared trapped.

Videos showed the towering hoarding billowing in the wind before collapsing on houses and a fuel station next to a busy road in the eastern suburb of Ghatkopar on Monday as a dust storm and rain lashed the city in the evening, bringing traffic to a standstill and disrupting flights at Mumbai airport.

Mumbai's municipal corporation (BMC) said at least 75 injured people were taken to hospitals following the accident and 31 have been discharged.

The agency owning the billboard did not have a permit from the BMC to put up the hoarding, the municipal body said in a statement. The hoarding measured about 1,338 square metres (14,400 square feet), it said, bigger than an Olympic pool's 1,250 sq m and nine times more than the maximum permitted size for a hoarding.

The BMC said it has instructed the agency to remove all its hoardings immediately.

"To prevent such accidents from happening again, instructions have been given to conduct a structural audit of all hoardings in Mumbai and immediately take down dangerous ones," Eknath Shinde, the chief minister of Maharashtra state of which Mumbai is the capital, said in a post on X.

About 25 people and some cars were still trapped under the crumpled hoarding, said a BMC official, who did not want to be named as he was not authorised to speak to the media.

Officials from fire services, police, disaster response and other authorities continued rescue operations that were taking longer because gas cutters could not be used at the site due to the presence of the fuel pump.