Several areas of Karachi plunged into darkness when two bomb blasts damaged the 220 kilovolt ampere (KVA) transmission line tower opposite the Zulfiqarabad Oil Terminal of Pakistan State Oil (PSO) in Razakabad on the National Highway at midnight on Saturday. One of the 52-metre high towers supported by four pillars fell due to the explosions, eyewitnesses said. An initial survey revealed that two of the tower's pillars each had half a kilogramme of explosives attached to them. The powerful impact of the blasts uprooted the other two pillars as well, bringing the tower down.According to the KESC spokesman, engineers have made arrangements to continue electricity supply through one circuit to meet the city's demand for power. Efforts would be made to repair the tower soon, he said, adding that re-erecting the tower might take 20 days.