KARACHI - Three members of a family died of suffocation inside a water tank when they went to clean it on Sunday.The house where the tragic mishap took place is situated at Zia Colony within the jurisdiction of Korangi police station. DSP Qasim Ghauri said that thirty-five year old Haji Akhtar went into the tank to clean it, but he fell unconscious due to gas suffocation. His two nephews Fayyaz, 22 and Imran, 18 went to help him but they also succumbed to the gas fumes and passed out.The family realised something was wrong and when they found them unconscious in the tank they asked for help. The neighbours pulled out the bodies and rushed them to the nearest private hospital where they were pronounced dead. Their bodies were sent to Jinnah Postgraduate Medical Centre for autopsy. The family hails from Bhawalpur and the victims were labourers by profession.