A massive power cut has caused disruption across northern India, including in the capital, Delhi.

It hit a swathe of the country affecting more than 300 million people in Punjab, Haryana, Uttar Pradesh, Himachal Pradesh and Rajasthan states.

Power Minister Sushil Kumar said 60% of the supply had been restored and the rest would be reinstated soon.

It is unclear why supply collapsed, but states using more power than they were authorised to could be one reason.