KARACHI: The blast took place at K Electric substation at Walika Chowrangi. No injuries or casualties have been reported so far. According to details, an explosion took place at K Electric substation at Walika Chowrangi area of Karachi. The surrounding walls collapsed due to the blast. Police and rescue personnel have reached the spot. Police officials said that the nature of the blast was being ascertained. A fire brigade vehicle reached the spot but no one was injured in the accident.