Hundreds of millions without power in India

More than half the country has been left without power after three grids collapsed - one of them for the second day running.

Hundreds of trains have come to a standstill and hospitals are running on backup generators.

In eastern India, around 200 miners have been trapped underground.

They have been moved to an area where they have access to fresh air and are not in immediate danger.

In Delhi, Metro services were halted and staff evacuated trains. Some trains have started running again, although a full service is not expected for many hours.

The breakdowns in the northern, eastern, and north-eastern grids mean around 600m people have been affected.

A failure on the northern grid on Monday caused severe disruption and travel chaos across northern India.

It was unclear why the grid collapsed but the power minister said some states might have been taking too much power.

After Monday's cut, engineers managed to restore electricity to the northern grid by the evening, but at 13:05 (07:35 GMT) on Tuesday, it collapsed again.

The eastern grid failed around the same time, officials said, followed by the north-eastern grid.

Areas affected include Delhi, Punjab, Haryana, Uttar Pradesh, Himachal Pradesh and Rajasthan in the north, and West Bengal, Bihar, Orissa and Jharkhand in the east.

An official in Orissa said the blackout in the eastern grid had been triggered by a fault and could take several hours to resolve.

Railway officials said more than 350 trains were stranded.

Across West Bengal, power went at 13:00 and all suburban railway trains on the eastern railways ground to a halt from Howrah and Seladah stations, the BBC's Rahul Tandon reports from Calcutta.

However, the city is not badly affected as it is served by a private electricity board, our correspondent adds.

Power cuts are common in Indian cities because of a fundamental shortage of power and an ageing 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.