Eleven people died and nine were hospitalised after a gas leak in Ludhiana in the northern Indian state of Punjab, a state lawmaker said on Sunday.

A team from the National Disaster Response Force was at the site along with a team of experts to determine the cause and source of the leak, said Rajinder Pal Kaur Chhina, a member of legislative assembly in Ludhiana.

Police officials were seen patrolling wearing masks and asking locals to keep out of a cordoned area, according to ANI news agency’s video feed on Twitter.

“The incident happened near a milk shop and a doctor’s clinic although we cannot say for sure where the leak began,” Chhina told Reuters by phone.

“People who came to buy milk in the morning, fell unconscious outside,” she said.

Punjab Chief Minister Bhagwant Mann tweeted the leak was from a factory, without providing further details.

Three bodies had “turned blue,” local resident Anjan Kumar said in ANI’s video feed on Twitter.