CNN-IBN television, quoting police, reported the incident occurred in an industrial section in the city's densely populated Sakinaka area and that three of those killed were from the same family.
"I saved six people but five of them, including three women, died," an eyewitness told the television channel. "We tried to help those three women but they were already dead."
The Press Trust of India news agency quoted fire officials that a fire also broke out after the explosion early in the morning.
The cause of the explosion was being investigated, but PTI quoted officials that they suspect it might have been the result of a gas cylinder blast.