Four workers had entered a sewer. They lost consciousness apparently due to poisonous gas. They were hauled up and doctors attended to them, they said.
DCP (Central) MS Randhawa said, "The hospital had outsourced the work of cleaning the sewer. We are probing the matter. One worker died and two fell ill."
The deceased has been identified as 45-year-old Rishipal. The two others are undergoing treatment, the police said. It is ninth such death in the national capital in over a month.