India's power network was back at full capacity on Wednesday after two days of massive outages that blacked out half the country and left more than 600 million people without electricity, The Times of India reported.


"Power has been restored fully across the northern, eastern and north-eastern grids," Power System Operation Corp chief SK Soonee said.


Monday's failure of the northern network, followed by the expanded collapse of all three grids after midday Tuesday caused chaos across a vast region, paralysing transport networks.


Hundreds of miners were trapped underground for hours in the eastern states of West Bengal and Jharkhand, metro services were stopped temporarily in the capital New Delhi and hundreds of trains were held up nationwide.


New power minister Veerappa Moily, who was appointed to the post in a Cabinet reshuffle even as Tuesday's unprecedented crisis was still playing out, admitted he faced an enormous task in restoring public confidence.


"It is a very difficult and challenging situation, and solutions will have to be found," Moily said in a series of interviews with Indian television networks, one of which was interrupted by a blackout.


According to senior ministry officials, the two successive days of grid failure had been triggered by energy-hungry states drawing power beyond their allocated limits.


"I'm not going to start with a blame game. The Centre and the states will have to work together on this," Moily said.


"The fact is that energy demand across India is huge, and we have to try and keep in touch with the pace of development," he added.


The massive power cuts left Indians angry and frustrated in cities across the affected region, as they struggled through gridlocked streets in the humid monsoon heat.