NEW DELHI (AP) — A large billboard collapsed onto people during heavy rain and thunderstorms in India's western city of Mumbai, killing at least 14 and injuring 74 others, reports said.

A rescue operation was ongoing Tuesday morning, and it was unclear how many people may still be trapped.

The rains, accompanied by high winds, caused the 30-meters-tall (100-foot-tall) billboard to fall over a gas station in the suburb of Ghatkopar on Monday evening. At least 47 people were rescued late into the night.

Police are investigating the incident and say the billboard was illegally installed, officials told the Press Trust of India news agency.

The officials said 31 of the injured had been discharged from the hospital.

India has heavy rain and severe floods during the monsoon season between June and September that brings most of its annual rainfall. The rain is crucial for agriculture but often causes extensive damage.