As many as 22 students of a girls’ school in south Delhi fell unconscious in class after a pepper spray can in a teacher’s bag accidentally leaked on Wednesday, officials said.

The students of Class 6 and 7 of the Government Girls’ Senior Secondary School in Chhatarpur fell unconscious soon after celebrating the birthday of a teacher and were rushed to Safdarjung Hospital for treatment. A police team also reached the hospital to investigate the case.

The cause was initially suspected to be a gas leak and the possibility of food poisoning was also looked into, as all the students had eaten the birthday cake.

DCP South Chandan Chaudhary said, “On inquiry, it was revealed that the students fell unconscious while they were celebrating the birthday of a teacher. We are looking further into the incident.”

The Delhi government said, “There was no gas leak at the school, but rather a can of pepper spray a teacher was carrying in her bag accidentally leaked. All affected students were immediately catered to and were provided the necessary help and treatment. The government is closely monitoring the health of the students,” it said on Wednesday.