A man was injured on Saturday after a low intensity bomb blast at a school ground in West Bengal's North 24 Parganas district, police said.
The incident happened at the Assembly of God Church School in Dum Dum cantonment area.
"The ground was being cleaned for a football match when one of the cleaners found a ball like object. When he threw it, there was an explosion, injuring him. The cleaner has been identified as Johnny Haldar," said a police officer.