At around 8 PM a cooking gas cylinder exploded in East Delhi's Gandhi Nagar area which triggered a fire in a house.
Walls of the house in which the cylinder exploded and the one opposite it, both collapsed under the impact of the explosion, a senior district administration official said.
The deceased were identified as Rajesh Goyal, Poonam and Soni Ram, all family members.
The injured were identified as Naina (4), Girish (6), Krish (12), Naushad (8), Sonu Kashyap (60), Ahmad and Abbas.
The injured persons were admitted at LNJP Hospital.
Seven fire tenders rushed to the spot and extinguished the blaze, a Fire Brigade official said.
The two houses were rented by persons identified as Arun and Jitender, both tenants of one Sanjay.
In the second incident which took place near southeast Delhi's Ashram Chowk, a 30-year-old woman, Mamta and her two daughters Kritika (9) and Priyanka (11 months) were charred to death in a fire that broke out in the building in which they lived.
At least 23 people were injured in the incident, police officials said.
Mamta and her daughters were stuck in their third floor flat in the building and could not escape and were charred to death, police said.
Many people were injured when they jumped from their balconies to escape the flames.
While some suffered burn injuries during the escape, remaining were injured while saving others, police said.
Three persons including a woman and a child sustained serious burn injuries, they said.