The largest power outage in history occurred across 22 Indian states, affecting more than 620 million people, or about 9 percent of the world's population.

Two severe power outages affected most of northern and eastern India on 30 and 31 July 2012. The 30 July 2012 blackout affected over 400 million people and lasted about 13.5 hrs. During that period, it was the largest power outage in history by number of people affected, beating the January 2001 blackout in Northern India. Similar conditions caused a blackout on the next day, which remained the largest power outage in history as of May 2025. The outage on 30 July affected more than 620 million people, spread across 22 states in Northern, Eastern, and Northeast India. An estimated 32 gigawatts of generating capacity was taken offline. Of the affected population, 320 million initially had power, while the rest lacked direct access. Electric service was restored in the affected locations between 31 July and 1 August 2012.

India is a federal union comprising 28 states and 8 union territories, for a total of 36 subnational entities. The states and union territories are further subdivided into 800 districts and smaller administrative divisions by the respective subnational government.