The Economic Times of India is reporting that a power outage covering half the country is likely to be the largest ever in India.
Nineteen of India's 28 states with a total population of 670 million people were without power, India's NDTV said, with the lights out even at major hospitals in Kolkata.
India's demand for electricity has soared along with its economy in recent years, but utilities have been unable to meet the growing needs. India's Central Electricity Authority reported power deficits of more than 8% in recent months.
More top news
Climate change is a pressing issue for Tonga, but has it had the attention it deserves at the Commonwealth summit?
With temperatures peaking at 29C today, it is the hottest April day for nearly 70 years.
Russian trolls are behind a disinformation campaign about chemical weapons attacks in Syria and Salisbury, a government source has said.