Power has been fully restored in India following a cascading blackout that left more than 600 million people without electricity.

Officials said Wednesday the power was back on in northern and eastern India, where Tuesday's historic outage affected people in 20 states.

The blackout was the second in as many days, after a smaller outage Monday cut power to more than 300 million people.

Indian Power Minister Sushil Kumar Shinde blamed Indian states for triggering the grid failure by drawing more than their allotted share of power. But the chief of India's Power Grid Corporation cautioned it was too soon to know for sure.

Limited power failures are common in India, but analysts say such large-scale outages highlight the weaknesses in the country's infrastructure as India strives to become an economic superpower.