The deceased have been identified as Manju, 40, Tanu, two years, and Daksh, four, police said.
The fire brigade received a call of building collapse from Mohan Colony at 2.46 a.m., a fire officials told IANS.
“A portion of the roof of the first floor building in which they were staying collapsed, resulting in the death of the two children and woman,” Deputy Commissioner of Police (West) Pushpendra Kumar told IANS.
The officer said that no construction work was going on in the building.
“The building was old and probably in bad condition, that’s why it fell,” the officer said.
The husband of the woman sustained minor injuries and was shifted to hospital, police added.