Torrential rains in the city have left scores injured and badly disrupted normal life which braced up to face more problems with the impending cyclone "Phet" expected to hit the coastal areas later on Sunday.
The heavy rains accompanied by thunderstorm that started late night on Saturday also left half of the city in darknes.
Police and rescue officials said they were reports of people being injured in road accidents and in flooding of low lying areas.
The rains also left most of the roads in the city flooded with many vehicles stuck in the heavy water flooding.
Those key roads blocked completely by rainwater included Shahrah-e-Faisal, M A Junnah Road, Boltan Road, Main Nazimabad Road, Rashid Minhas Road, Liaquatabad Road, University Road and many others.
Heavy rains and thunderstorms hit the coastal area of Gwadar and parts of interior Sindh yesterday evening leaving thousands displaced.
Around 40 villages in Gwadar, were reported to be washed away by the heavy rains.
Commander Coast Pakistan Navy, Vice-Admiral Tayyab Ali Dogar told the media that Karachi would remain safe from the impending cyclone as it had lost its intensity to category two and will further weaken to category one when it will landfall between Karachi and Pasni with wind speed between 35 to 40 knots.
The Admiral said Karachi being the built up area does not face much danger whereas the areas outside the metropolis where there are no built up areas would be vulnerable.
He stated there would be not much impact of the cyclone on the land.