Many cities across Pakistan plunged into darkness on late Sunday evening due to a technical fault at the National Power Control Centre (NPCC) in Islamabad, Express News reported.
NPCC consultant Chaudhry Masood said the system collapse was due to a HUBCO power plant trip, which caused a 1200-megawatt shortage.
Cities affected include Karachi, Lahore, Rawalpindi, Quetta, Sibbi, Hyderabad, Tando Mohammad Khan, Badin and Nawabshah.
27 grid stations were reported to have tripped in Karachi. 80 to 90 per cent of the city was blacked out.
Restoration of power in Karachi was top priority because of the Karachi Stock Exchange, said Secretary Water and Power Rai Sikander.
Lahore Airport was blacked out but continued operations by running generators.
16 divisions of Balochistan were in darkness.
Officials from the NPCC said they had traced the cause of the technical fault, but could not give a time frame on how long it would take to fix.
Off-duty NPCC officials were called in to assist with the situation.
The KESC depends on the National Grid Centre for a 500-600 megawatt supply of electricity.
Prime Minister Raja Pervez Ashraf took notice of the blackout.