A general view of an electric power station on the outskirts of Jammu July 31, 2012. Grid failure hit India for a second day on Tuesday, cutting power to hundreds of millions of people in the populous northern and eastern states including the capital Delhi and major cities such as Kolkata. [Photo/Agencies]

A teacher (C, top) conducts a lesson for students in the light of kerosene lamps and a candle during a power-cut inside a house in Kolkata July 31, 2012. Hundreds of millions of people across India were left without power on Tuesday in one of the world's worst blackouts, trapping miners, stranding train travellers and plunging hospitals into darkness when grids collapsed for the second time in two days. [Photo/Agencies]