India suffered its second huge, crippling power failure in two days Tuesday, depriving as much as half of the vast country, up to 600 million people, of electricity and disrupting transport networks for several hours.
The first power grid collapse, on Monday, was the country's worst blackout in a decade. It affected seven states in northern India that are home to more than 350 million people.
But Tuesday's failure was even larger, hitting eastern and northeastern areas as well. Both blackouts cut power in the Indian capital, New Delhi, and left people sweltering in high heat and humidity.
Power was largely restored as of 9:30 p.m., several hours after the affected electricity grids collapsed, the Power Grid Corporation of India reported on its website.
New Delhi was back at 100%, as was the northeastern region, while the northern region that includes New Delhi had an 80% power supply, the corporation said.
But only 58% of the power supply had been restored in the eastern region, it said.
With about 1.2 billion people, India has the second-highest population of any country, behind China.
At least 300 trains were held up in the affected regions, said Anil Kumar Saxena, a spokesman for Indian Railways. New Delhi's metro system, seen as a lifeline for commuters, also suffered delays before power was restored, causing chaos for many travelers.
The two consecutive days of disruption are embarrassing for India, a nation growing in international stature and the third-largest Asian economy, and have raised questions about its investment in infrastructure.
The power companies involved said they were working to restore service.
During the blackout, one traveler in New Delhi told CNN-IBN that her journey home had taken almost three hours, rather than the usual 40 minutes. "Long night ahead, with no lights -- I've got my trusty solar lamp ready for the night," she said.
An elderly woman said she was petrified that water would run out, but she said she would rely on candles and torches to get through the power outage, which she blamed on poor governance
Other travelers told CNN-IBN of ruined plans to visit relatives and long waits at stifling stations.
Miners in the Burdwan District of West Bengal state were hit by the blackout too.
The district's top administrator, O.S. Meena, told CNN that 150 coal miners were working underground when the outage happened, stopping lifts.
Authorities switched to emergency supplies to run elevators to bring the miners up, and more than 60% have been brought above ground, he said.
"The others will be brought up very soon. All are safe," Meena said.
Authorities urged people not to panic about the safety of the miners.
Monday's grid failure struck in the early morning. Residents spent the rest of the night drenched in sweat amid humid weather, and many backup power systems had run out by daybreak. Power was partially restored after about six hours, authorities said.
That blackout left passengers stranded at train stations, and signal failures caused traffic snarls that choked the Indian capital's already congested roads during office hours.
Airports and hospitals have been running on backup power, so have remained operational, but many businesses say they have lost out because the blackouts have cut productivity, said Jyoti Kamal, senior editor for CNN-IBN.
The blame game between political parties has already begun, Kamal said, but the root cause of the problem is that demand is surging but power generation is just not keeping pace.
Many people, especially in northern India, are hugely frustrated by the problem, he said.
Indians have not been strangers to power cuts, which become more common during the summer when demand shoots up. India has an annual power shortfall of 8%.
Some of the increased demand this summer has been caused by farmers using more energy for irrigation and other tasks, in part because monsoon rains are down by more than a fifth since the start of monsoon season on June 1. People are also using air conditioning units more to cope with high humidity.
The monsoon rains are very important not only because they provide rain for agriculture and hydroelectric power, but also for their natural cooling effect, according to CNN meteorologist Brandon Miller.
Temperatures have been in the mid-90s Fahrenheit, but humidity at over 80% is making it feel like well over 100 Fahrenheit. This makes it harder for buildings to cool down at night, and harder for humans to cool through evaporation of perspiration, all leading to higher energy demands, Miller said.
The Indian power minister, Sushilkumar Shinde, has ordered an investigation into Monday's outage. He said the last time that an entire grid failed in north India was 10 years ago.
He said that the reason for the latest blackouts is not yet known but that some states, particularly those with a lot of agricultural activity, may have been using more than their share of energy.
Prakash Javadekar, of India's main opposition Bharatiya Janata Party, criticized the government for what he said was "a huge failure of management in the power sector."
India relies on coal for much of its energy needs but also uses hydroelectric power, which has been affected by the delay in monsoon rains.
Observers say the crisis has exposed the need for India to update its infrastructure to meet the power needs of businesses and the country's growing population.
"Economic growth is constrained by inadequate infrastructure," among other factors, the U.S. State Department's country report on India says.
"Foreign investment is particularly sought after in power generation," it adds, as well as areas including telecommunications, roads and mining.
The United States is India's largest investment partner, the State Department report says, with U.S. direct investment in India estimated at more than $16 billion through 2008.