Mohammad Saleem Khan and Abdul Rashid Kallu, both residents of Srinagar, fell unconscious after inhaling a "mysterious" gas which emanated from the ground while they were digging a well in Sikanderpora locality, a police spokesman said.
He said both of them were taken to a hospital where Khan was declared brought dead, while Kallu was referred to SKIMS hospital for specialised treatment.
Khan's body was handed over to his relatives for last rites, the spokesman said.