ISPs in India also have backup plans that should keep all-important Internet connectivity in place, but there may be some trouble spots at the access portions of their networks that could cut off some facilities, Ahuja says.

"In the past there have been significant outages," he says, "but nothing as significant as this."

The chairman of the Power Grid Corporation of India said the exact cause of the power cut was unclear, but that it appeared to be due to the "interconnection of grids." "We have to see why there was a sudden increase in load ... we will make sure that such a situation is not repeated," according to a BBC report.

The BBC report went on to say power cuts are common in Indian cities because of a fundamental shortage of power and an aging grid -- the chaos caused by such cuts has led to protests and unrest on the streets in the past. But the collapse of an entire grid is rare -- the last time the northern grid failed was in 2001.

India's demand for electricity has soared in recent years as its economy has grown but its power infrastructure has been unable to meet the growing needs. Correspondents say unless there is a huge investment in the power sector, the country will see many more power failures, the BBC wrote.