The NHRC issued notices to the chief secretary, Delhi government and the police commissioner.
The owner of a semi-built plot, where two workers died while cleaning a septic tank, was arrested for alleged negligence, police said on Wednesday. Delhi Chief Minister Arvind Kejriwal met the family members of the victims in the evening and promised a compensation of Rs 10 lakh to the kin of the deceased.
The BJP accused the Aam Aadmi Party dispensation of negligence, while the National Human Rights Commission sought a report from the Delhi government, the police and chief secretary.
Earlier on Tuesday, two contractual workers died and three others were hospitalised after apparently inhaling toxic gas when they entered a septic tank of the plot at Bhagya Vihar area of Prem Nagar in Rohini.
"Gulam Mustafa, the owner of the semi-built plot, has been arrested late on Tuesday night," Deputy Commissioner of Police (Rohini) S D Mishra said.
The plot has a 10-foot-deep septic tank, in which Mustafa and a mason named Rambir allegedly asked two labourers to go inside for cleaning on Tuesday. The labourers refused to clean the tank since they were not trained, but they were forced to enter after being blackmailed with not getting paid three days of wages, the police had said.
"The chief minister met us on Wednesday at around 6 pm and assured that the family of the deceased persons would get Rs 10 lakh and jobs," said Jaya Vardha, elder sister of one of the deceased.
Vardha added Kejriwal told them that the injured persons would get free treatment and the government would bear there expenses.
The NHRC issued notices to the chief secretary, Delhi government and the police commissioner, asking for a detailed report within six weeks.
The commission has also asked the Delhi government to inform whether it had issued any guidelines prohibiting unauthorised construction and cleaning of septic tanks and, if so, why its strict compliance was not being ensured. It has directed the Delhi government to chalk out appropriate instructions to deal with the issue and inform.
"The death of two workers due to inhaling poisonous gas during the cleaning of sewer in Prem Nagar area of Outer Delhi was due to the negligence of the Delhi government," Vijender Gupta, the leader of Opposition in the Delhi Assembly, said at a press conference.
Gupta said that the AAP was "insensitive" to the plight of the sanitation workers, saying the latest incident proved the allegation.
"These workers are from poor families, but their tragic death due to poisonous gas has again made it clear that the Delhi government is not serious about saving lives of manual scavengers from these accidents, their rehabilitation and improving the condition of working," he added.