India has been hit by a massive blackout due to a collapse of the northern and eastern grid networks.

The collapse took place at 2:30am local time yesterday; it is one of the world’s most widespread power failures and one of the most severe in the country, affecting 600 million people in nine states, reports the Economic Times.

"Power has now been restored in parts of Punjab, Delhi, Jammu and Kashmir, Himachal Pradesh and the city of Lucknow in Uttar Pradesh."

Indian power minister Sushil Kumar Shinde confirmed the blackout, but told local television that essential services, such as railways and the metro would be restored today.

Power has now been restored in parts of Punjab, Delhi, Jammu and Kashmir, Himachal Pradesh and the city of Lucknow in Uttar Pradesh.

A committee has been appointed by Shinde to investigate the causes of the power failure, with a report expected to be submitted in the next two weeks.

Metro rail services in Delhi, as well as Howrah, Asansol and Sealdah, were stopped because of the unexpected blackout, and up to 500 trains across the country may have been stranded without electricity, the news site reported.