All three injured were shifted to the nearby government hospital and are said to be in critical condition.

The police informed that the cracker-manufacturing unit was operating from the house of one Pintu Mandal in the Sardar Para area of Haral village in Champahati under Baruipur police station.

The house was destroyed owing to the intensity of the explosion. A fire started from the explosion and burnt down the house.

The police suspect that the blast occurred during the manufacture of ‘socket crackers’. A huge police force has been deployed in the area. The police are investigating whether the factory had the requisite licence or not.

Last month, a blast occurred at an illegal firecracker factory in Howrah’s Uluberia, damaging more than 10 houses in the neighbourhood. Two days before that incident, three children died in another such blast at Gangarampur in Uluberia.

In May this year, a blast occurred at a Budge Budge house stacked with illegal firecrackers. Due to the blast, two women and one child died on the spot. The police arrested the owner of the house.