Power Grid Corp. of India said on its Web site that the lights were largely back on as of 9:30 p.m., including 100 percent of the capital, New Delhi, CNN reported. However, the outage continued for about 58 percent of the people in the country's eastern region
At its peak the massive outage affected half of India's 1.2 billion people. Officials said the blackout was one of the world's widest spread power failures.
The lack of electricity brought out frustration among Indians and criticism of the government. Prakash Javadekar of India's main opposition Bharatiya Janata Party called the blackout "a huge failure of management in the power sector," CNN said.
"For the last two days the country is suffering. This is an unparalleled occurrence," Javadekar said. "The whole machinery has failed to locate the exact fault and yet pushed the entire load onto it."
An initial power grid failure Monday had affected seven states in northern India, but Tuesday's failure was larger, affecting 12 states, FirstPost India reported.
The grid breakdown was blamed on transmission line failures, FirstPost India said.
The eastern grid's failure and the resulting outage in Kolkata led to West Bengal Chief Minister Mamata Banerjee closing government offices and schools.
At least 300 trains were held up in the affected regions, Indian Railways spokesman Anil Kumar Saxena said. FirstPost India reported partial service had resumed on all lines of the Delhi metro. Officials said some railway lines also were functioning
Power Minister Sushilkumar Shinde ordered an investigation into Monday's outage, CNN reported. He said the last time an entire grid failed in northern India was 10 years ago.