NEW DELHI – Northern India's power grid crashed Monday, halting hundreds of trains, forcing hospitals and airports to use backup generators and leaving 370 million people — more than the population of the United States and Canada combined — sweltering in the summer heat. The blackout, one of the worst to hit India in a decade, highlighted the nation's inability to feed a growing hunger for energy as it strives to become a regional economic power. The northern grid crashed about 2:30 A.M. because it could no longer keep up with the huge demand for power in the hot summer, officials in the state of Uttar Pradesh said. However, Power Minister Sushil Kumar Shinde said he was not sure exactly what caused the collapse and had formed a probe committee. The grid feeds the nation's breadbasket in Punjab, the war-wracked region of Kashmir, the burgeoning capital of New Delhi, the Dalai Lama's Himalayan headquarters in Dharmsala and the world's most populous state, the poverty stricken Uttar Pradesh. New Delhi residents were roused from sleep when their fans and air conditioners stopped and came out of their homes in the heat as the entire city turned dark. Metro transit system, with 1.8 million daily riders, stopped for hours during the morning commute. Some trains across the northern region were stranded when their electric engines failed. Earlier this month, hundreds of thousands of people from the US Midwest to the Mid-Atlantic spent the Fourth of July like America's founders did in 1776, without the conveniences of electricity. Power outages from a storm altered planned celebrations in a host of ways and left powerless residents grumbling that America's birthday would hardly be a party. And in Saudi Arabia, where temperatures are among the highest in the region, the onset of Ramadan has resulted in a series of power outages. — Agencies