Four more people, who were taken ill, were undergoing treatment at a hospital, they said.
However, Ludhiana Deputy Commissioner Surabhi Malik said it was likely that some chemical reacted with methane in manholes.
“We are going to collect samples from manholes. It is quite likely that some chemical reacted with methane in manholes,” she said.
“It is likely that the deaths were caused by a neurotoxin,” Malik added.
As it was a thickly-populated area, the immediate priority was to evacuate people from the place, the official further said.
She said once the nature of chemical reaction is ascertained, the details will be shared.
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.
She said there was no need to panic and asked people not to fall prey to rumour mongering. She also appealed to people to stay away from the area. “But a check will be conducted to see how far this gas spread”.
She further said that CCTV cameras were being scanned.
Earlier, an NDRF official said it was yet to be found out which gas led to the tragedy. “We will check it first then we will let you know,” said the official in a response to the type of gas.
“The incident of gas leak in Giaspura area of Ludhiana is very painful. Teams of police, district administration and NDRF are present on the spot. Every possible help is being provided..,” Mann said in a tweet in Punjabi.
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