The man had been living in the shop illegally, police sources said.

The body was discovered by Sharjah Civil Defence when workers of an adjacent cafeteria witnessed smoke coming out of the premises as a car inside the shop caught fire.

They reported the issue to the police operations room as well as to the Civil Defence around 5.30am, who rushed a team immediately to the scene of the incident to put out the blaze.

Police said there was a malfunction with car’s air-conditioning system resulting in a gas leak. The car had run out of fuel and the gas leakage led to the fire.

The deceased’s body was transferred to the forensic laboratory for an autopsy. He has three children in Pakistan, two boys and a girl.

“There should be no laxity in safety procedures and such violations that risk workers’ lives attract severe punishment,” said a police official.

Police examination of the scene revealed that carbon monoxide levels were as high as 70 to 75 per cent. Forensic laboratory reports ruled out foul play.

The manager of the shop has been taken into police custody for interrogation as the shop owner was in Pakistan at the time of the incident.

The incident prompted a Sharjah Civil Defence senior official to warn the public against sleeping in any enclosed space within which a car engine is running. He described it as a potential “slow death”.

Lieutenant Colonel Sami Khamis Al Naqbi, director-general of Sharjah Civil Defence, told Gulf News that exhaust fumes from a running car engine can deplete oxygen in the atmosphere and slowly asphyxiate victims in as little as one hour.

Carbon monoxide is a tasteless, colourless and odourless gas which binds with red blood cells, restricting the flow of oxygen which can lead to suffocation.

He said a car engine emits toxic exhaust, so under no circumstances should people try running a generator [or any other engine-driven tool] inside the house, basement, garage, screened-in porch or any enclosed space — not even if the the doors and windows are kept open.