Irshad (40) and his wife Sunno (32) were rushed to a hospital, SP (City) Praveen Ranjan Singh said.
Irshad used to play fireworks in marriages. He used to store these in a huge quantity at his house without a valid license, police said.
Three children of the couple were also injured in the incident, Singh said.
"Irshad had no license to store the fireworks and a case under the Explosives Act 1884 has been registered against him," he said.