A woman and her two children were crushed to death in their sleep when the roof of their first-floor house collapsed in west Delhi's Uttam Nagar area on Monday.
The deceased were Manju, 40, and her children Tanu, 2, and Daksh, 4, police said.
The Delhi BJP accused the AAP-led Delhi government of "criminal negligence", a charge denied by the Aam Aadmi Party.
Delhi Bharatiya Janata Party chief Satish Upadhyay, who met the family of the deceased, said the accident was caused as the Delhi government had laid sewer lines in the area. He termed it an act of "criminal negligence".
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 the victims were staying collapsed, resulting in the three deaths," Deputy Commissioner of Police (West) Pushpendra Kumar told IANS.
The officer said no construction was going on in the building.
"The building was old and probably in bad condition, that's why it fell," the officer said.
The woman's husband sustained minor injuries and was shifted to hospital, police added.
According to area residents, the Delhi Jal Board has been laying drain pipes for the last two years but the work has not been completed yet.
"During rains, water accumulating in the pipeline enters the houses," area resident Mukesh Sharma told IANS.
"Sewerage work of the DJB in the area may have led to the incident," he added.
Upadhyay said: "It's criminal negligence on part of Water Minister Kapil Mishra, AAP MLA Naresh Balyan, officials of the DJB (Delhi Jal Board) and the DSIIDC (Delhi State Industrial and Infrastructure Development Corporation)."
Upadhyay said Mishra and Balyan had full knowledge about waterlogging in about 20 houses in the area due to "negligence" in the work of laying sewer lines.
"They did not take any concrete steps to solve this problem though the locals had brought this case to the knowledge of Chief Minister Arvind Kejriwal and Deputy Chief Minister Manish Sisodia several times," he said.
Balyan, the AAP legislator from Uttam Nagar, denied the BJP's allegations terming them as baseless. "All the allegations of the BJP are baseless," Balyan told IANS.
"No politics should be done on this issue," Balyan said, adding that "drainage and waterlogging issues lie with the MCD (municipal corporations of Delhi)".
DJB officials could not be contacted despite repeated attempts.