KARACHI, Feb 5: A huge explosion in the Clifton area on Tuesday caused panic and triggered the movement of ambulances and police mobiles in the locality, though it later emerged that the blast was caused by sewer gases.

Area people said a huge explosion was heard on Racecourse Road near the Cantonment railway station, which also broke the glasses of nearby buildings’ windows. A large number of people gathered in the area but failed to find the source of the explosion.

“But later, the side-wall of a nearby building was found damaged, which made us call the BDU (Bomb Disposal Unit) team,” said a Frere police station official. “The team reached the spot after a few minutes and did not find any explosive remains and finally concluded that the explosion was triggered inside the sewer lying parallel to that particular area,” he said.

The officer said the ambulances that reached the spot were called by the police as a precautionary measure, but returned within half an hour after the situation cleared up.

A BDU official said sewer gas usually caused such explosions in the area, which suggested a flaw in the line passing through Racecourse Road, adding that it needed immediate action from the authorities concerned.

“Usually, it is ammonium nitrate that creates such big explosions due to some blockade or other reasons, which can be better defined by the people concerned,” he said.