One person was arrested and three others detained for interrogation in connection with a blast in the Colonelgunj area of the city, police said in kanpur on Wednesday.
Police arrested Kamal Kumar Sahu, who runs a general store near the site of the blast that left seven people, including four children, injured last night.
A large number of crackers were recovered from the shop, Dayanand Mishra, Superintendent of Police (West), said.
Sahu did not have the required license to sell the crackers and was arrested for illegally storing and selling them, he added.
However, Mishra said that it was too early to say whether Sahu was related to the blast.
The low-intensity bomb was packed in a polythene packet on a cycle. Mishra said three others have been detained for interrogation.
Police is trying to trace the owner of the cycle, he said.