For two consecutive days in July, India experienced blackouts that took down large portions of the country's power grid. The second outage was the largest in history, leaving more than 600 million people, nearly a tenth of the world's population, without electricity. The blackouts brought renewed attention to the country's power sector, which is struggling to supply India's growing demand. They exposed weak links in the transmission system, inadequate fail-safe systems for preventing cascading failures, and a lack of proper outage planning.