About 50 people were rescued. A man and a woman were rushed to hospital after they inhaled smoke but it was too late.
Multiple families live as tenants in the ground-plus-four building in Mamura village in Sector 66.
The fire appears to have been sparked by an electric two-wheeler being charged inside the building. It spread to nearby petrol-powered two-wheelers parked in the premises, said Joint Commissioner of Police Rajiv Mishra.
Fire tenders, including a hydraulic platform, were rushed to the spot immediately after the blaze was reported and most residents were safely evacuated.
"Two persons, who already had health-related issues, fell ill after inhaling smoke and were shifted to the district hospital by ambulance," Mishra told reporters.
