The fire broke out around 1.00 pm in the JJ cluster near Behlolpur village under Phase 3 police station limits, according to officials.
Those injured have been hospitalised and the blaze controlled by the Fire Department, the police said in a statement.
All six persons were hospitalised and five of them discharged after treatment but the condition of a woman in the family was stated to be critical, the police said.
The fire was reported around 1.15 pm in Ecotech Extension 1 area and firefighting is underway, the officials said.
The fire in the building in the industrial Sector 59 of the NCR city was reported around 6.15 pm and around 90 per cent of it was controlled by 8.30 pm, the police said.
A short circuit possibly triggered the fire in one of the warehouses, which then spread into the other, according to the official.