More than 700 million people in India—about 10 percent of the world’s population—endured history’s largest power outage on July 31, 2012. The massive electrical blackout was the second to strike the nation in two days, with the first having left 370 million people without electricity.

“Everything was out,” a BBC reporter told PRI’s The World. “Not just in the homes. On the streets, there were no traffic lights. Delhi’s subway, the Metro, was completely halted. People had to be evacuated off the trains. The city was grid locked. There were thousands of people out on the streets.”

Both outages, which delayed transportation systems, trapped miners for hours, left millions without air-conditioning, and cost millions of dollars, highlighted the developing nation’s inability to keep pace with the energy demands of its booming population.

While the cause of the double blackout is under investigation, Indians blame them on poor investments in the infrastructure of the world’s fourth-largest energy consumer.

“Underinvestment at both the state level and national level has been building as power demand increases,” said Charles Ebinger, director of the Energy Security Initiative at the Brookings Institution. “This is just a colossal case where everything has come home to roost after years of neglect.”

The nation faces complex energy challenges. According to The New York Times, “…about 300 million people in India have no access to power at all, and 300 million more have only sporadic access…Another of the nation’s basic problems is that supplies of coal, largely controlled by the government, have not been enough to meet demand even among power plants that have the capacity to generate more electricity.”

Unpredictable weather has also exacerbated the country’s energy demands. Diminished rainfall due to a weak monsoon season has lowered hydroelectric generation and pushed farmers to use electric pumps for irrigation. This has further put a strain on the nation’s ability to power itself.

According to The Economist, “…a decline in average rainfall may not be the main worry. Experts who met in Delhi in May to discuss climate-induced ‘extreme events’ in India suggest that likelier threats include more short and devastating downpours and storms, more frequent floods and droughts, longer consecutive dry days within monsoons, more rapid drying of the soil as the land heats, and a greater likelihood that plant and animal diseases might spread.”

“It does not bode well for farmers, or for crammed cities with poor sewerage and other rotten infrastructure,” the media outlet added.

The unusual heat and humidity has also prompted many to use additional power for air-conditioning systems.

“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,” USA Today reported. “Temperatures in the city were in the mid-30s C (90s F) with 89 percent humidity.”

India’s outages have raised concern that such failures could occur in more developed, electricity-reliant nations.

Although United States federal officials have stated that an outage on the scale of India’s is “very, very unlikely,” they do admit that the power grid is extremely prone to cyberattacks, which are considered one of the nation’s biggest domestic terrorism fears.

“The threats to systems supporting critical infrastructures are evolving and growing,” a U.S. Government Accountability Office report stated.

The document later added, “A successful attack could result in widespread power outages, significant monetary costs, damage to property, and loss of life.”