The child, identified at Bibhas Ghosh, was injured in the explosion that took place at 9.30 am in a fruit stall in the market.
The cause of the explosion has not yet been ascertained, police said adding, "It was a high-intensity blast. Of the 10 injured in the blast, four were seriously affected. Found some iron nails but can't ascertain cause of the blast yet as there is no smell of gunpowder."
West Bengal Minister for Technical Education Purnendu Basu even compared the attack to "the ones carried out by the Rashtriya Swayamsevak Sangh", he said, "I think this type of blast is similar to the ones carried out by RSS elsewhere."
The injured in the explosion have been admitted to RG Kar Medical Hospital and College.
The area falls under the jurisdiction of Barrackpore Police Commissionerate, and police rushed to the spot.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)