The killed labourer was identified as 25-year-old Shahrukh, a resident of Bulandshahr. (Representational)

A labourer died and two others were missing after being swept away while working on a project to construct a cemented wall over a 30-foot-deep drain in west Delhi's Khayala area, police said on Friday.

The three labourers were swept away when the Delhi Jal Board (DJB), which had stopped the water flow in the drain for the said work, suddenly resumed the supply, officials said.

The killed labourer was identified as 25-year-old Shahrukh, a resident of Bulandshahr in Uttar Pradesh, the police said, adding that 19-year-old Ankit, a resident of Hardoi in Uttar Pradesh, and 25-year-old Devinder Sharma, a resident of Etah in Uttar Pradesh, were missing.

The DJB had given the contract for the construction of the wall to a private company, the police said.

Twelve labourers were working on the project on Friday. At around noon, Shahrukh, Ankit and Devinder Sharma entered the drain to take the measurements for its cover. Meanwhile, someone allegedly resumed the water supply and the three were swept away, the police said.

The fire department was alerted at 12.35 pm and three fire tenders were rushed to the spot. The police were informed at around 1 pm.

"The fire officials successfully pulled out Shahrukh while the other two workers could not be traced till now," Deputy Commissioner of Police (West) Monika Bhardwaj said.

Shahrukh was rushed to the Deen Dayal Upadhyay Hospital, where he was declared brought dead, she added.

An initial investigation revealed that Pratibha Industries was given the contract by the DJB to construct the wall over the drain, which was used for treatment of water before being sent to the Yamuna river, the police said, adding that a case was registered against the contractor.

The DJB termed the incident "unfortunate" and said the work at the site was related to an "interceptor sewer project".

A DJB team, led by its Vice Chairman Dinesh Mohaniya, visited the accident site. Mr Mohaniya said, "We stand with the families of the deceased and those missing in this hour of crisis. Compensation will be given to them."

The DJB said the project was given to the Engineers India Ltd (EIL), which had sub-let it to Pratibha Industries. "EIL is responsible for the execution and day-to-day monitoring of the work. We only monitor the progress at monthly meetings," a DJB official said.