The incident took place in a residential building owned by one Amar Singh who stays there with his four sons and wife in Farsh Bazar at around 4:55 pm, a senior police official said.
The police team which reached the spot detected smell of explosives at the site and felt that the roof may have collapsed due to a blast.
Immediately, senior police officials rushed to the spot.
"The cause of blast is not known yet. Only a detailed forensic examination can say what caused the blast. Prima facie, there is no foul play in the incident," Delhi Police spokesperson Rajan Bhagat said.