Still to recover from the blackout that lasted several hours this past Friday, Delhi and its satellite towns were subjected to yet another power shutdown on Sunday morning as more than 37 supply lines of 400 kV power grids tripped. Most parts of West, East and North Delhi experienced prolonged power cuts. In some areas of North Delhi residents complained of power cuts from 11 p.m. on Saturday till late Sunday afternoon. Senior Power Department officials blamed the "abnormal weather conditions' for the tripping of supply lines. "The tripping has again been caused by the presence of fog. It is abnormal to have fog at this time of the year, but the recent tripping of lines is solely a result of the fog and pollutants in the atmosphere,' explained S. R. Sethi, Director Operations of the Delhi Transco Limited. Of the 37 lines that tripped, about five belonged to Delhi. "These lines trip when fog and pollutants settle on the insulators of the power plants and cause what is called a flash-over on the insulators,' he said. Owing to the tripping, several power plants including Dadri, Badarpur, Bamnauli and Panipat were incapacitated. And it was not just the residents who had to bear the brunt of the power cuts, train movement on the Delhi-Kanpur and the Ambala-Delhi sections was disrupted. While more than 30 trains were delayed, seven trains had to be rescheduled. While the 2324 New Delhi-Howrah Express was diverted to run via Palwal-Agra-Tundla, the 3049 Howrah-Amritsar Express train was terminated at Ambala and remain cancelled between Ambala and Amritsar on Sunday. However, the Delhi metro railway services were spared and train movement continued without glitches. "There was no disturbance in metro movement. We were able to draw power from our sub-stations of Delhi Transco, which supply power at six locations -- Line I -- Kashmere Gate and Rithala; Line-II -- New Delhi and Indraprastha; and Line-III