Eleven people were killed after a gas leak incident in the Giaspura area in Ludhiana on Sunday, police said.
Four more people, who were taken ill, are undergoing treatment at a hospital, they added.
The source of the leakage and the type of the gas are yet to be ascertained, police said, adding that the area has been sealed while a fire brigade and an ambulance have been deployed there.
'In all likelihood, there is some gas contamination which has happened. It is quite likely that maybe some chemical reacted with methane in manholes. All of this is being verified,' Surabhi Malik, Ludhiana's Deputy Commissioner said
A 50-member team of the National Disaster Response Force (NDRF) has also reached the site.
Police said the casualties comprise five females and six males. Two boys aged 10 and 13 are among the 11 who died in the incident, they said.
As it was a thickly-populated area, the immediate priority was to evacuate people from the place, the official further said.
Punjab Chief Minister Bhagwant Mann said the incident was very painful and added that all possible help is being provided.
(with PTI inputs)