The death toll from a heatwave in Pakistan southern province of Sindh climbed to 500 on Tuesday, officials said, as thousands more battled for life at hospitals, dpa reported. More than 450 people had died in the port city of Karachi since Friday, provincial health minister Jam Mehtab Dahar said. The temperature in the city had been hovering around 45 degree Celsius for three days, said Ghulam Rasool, director general of the Pakistan Metrological Department. The death toll could rise because about 4,000 people were being treated at hospitals for heat stroke or exhaustion, said Ijaz Afzal, a director at the provincial health ministry.