NEW DELHI >> India’s energy crisis cascaded over half the country today when three of its regional grids collapsed, leaving 620 million people without government-supplied electricity for several hours in, by far, the world’s biggest blackout.

Hundreds of trains stalled across the country and traffic lights went out, causing widespread traffic jams in New Delhi. Electric crematoria stopped operating, some with bodies half burnt, power officials said. Emergency workers rushed generators to coal mines to rescue miners trapped underground.

The massive failure — a day after a similar, but smaller power failure — has raised serious concerns about India’s outdated infrastructure and the government’s inability to meet its huge appetite for energy as the country aspires to become a regional economic superpower.

Power Minister Sushil Kumar Shinde blamed the new crisis on states taking more than their allotted share of electricity.

“Everyone overdraws from the grid. Just this morning I held a meeting with power officials from the states and I gave directions that states that overdraw should be punished. We have given instructions that their power supply could be cut,” he told reporters.

The new power failure affected 620 million people across 20 of India’s 28 states— about double the population of the United States. The blackout was unusual in its reach, stretching from the border with Myanmar in the northeast to the Pakistani border about 1,870 miles away. Its impact, however, was softened by Indians’ familiarity with frequent blackouts and the widespread use of backup generators for major businesses and key facilities such as hospitals and airports.

Shinde later said power was fully restored in the northeast grid four hours after it went down, and that the north grid had 45 percent power and the east grid 35 percent. R.N. Nayak, chairman of Power Grid Corp., which runs the nation’s power system, said he expected to have full power later in the evening.

Oddly, as the crisis dragged into the evening, Shinde was promoted, becoming India’s home minister, its top internal security official. The promotion had been planned previously as part of a greater Cabinet shuffle before he presided over the world’s two worst power outages.

The outages came just a day after India’s northern power grid collapsed for several hours. Indian officials managed to restore power several hours later, but at 1:05 p.m. Tuesday the northern grid collapsed again, said Shailendre Dubey, an official at the Uttar Pradesh Power Corp. in India’s largest state. About the same time, the eastern grid failed and then the northeastern grid followed, energy officials in those regions said. The grids serve more than half India’s population.

In West Bengal, express trains and local electric trains were stopped at stations across the state of West Bengal on the eastern grid. Crowds of people thronged the stations, waiting for any transport to take them to their destinations.

Chief Minister Mamata Banerjee said it would take at least 10 to 12 hours to restore power and asked office workers to go home.

“The situation is very grave. We are doing everything to restore power,” West Bengal Power Minister Manish Gupta said.