The deceased were identified as Usha (45) and her mother-in-law Satyawati (75). Among the injured were Usha's husband Rishi Agarwal, daughter Neha, and son Saurabh, said a senior police officer.
Usha's youngest son, Gaurav, escaped unhurt with the help of neighbours.
The incident took place around 6.10 am, following which four fire tenders were rushed to the spot and the victims to a hospital, where two were declared dead on arrival, said the official.
Meanwhile, it took more than an hour for the firefighters to douse the flames, following which a cooling operation was launched, said a fire official.
The Agarwals live on the second floor of a four-storey building at Saadh Nagar locality in Palam. Rishi, a businessman, had rented the apartment around four months ago, police said.
Preliminary investigation revealed that there was a potential leakage in the LPG cylinder which exploded after Usha lit the stove today to make morning tea for the family.
By the time, the other members could react, the fire spread within the apartment and was later controlled from spreading to neighbouring areas.
However, several houses nearby witnessed cracks on the walls by the impact of the cylinder explosion, police said.
