India restored its power supplies on Wednesday after two days of massive outages that blacked out half the country, but fears remained that the grid could again collapse under the strain of over-demand. India's electricity network was back at full capacity after three regional grids failed on Tuesday in the country's worst power crisis  that left more than 600 million people without supplies. "It is a very difficult and challenging situation, and solutions will have to be found," new Power Minister Veerappa Moily said after confirming that the northern, eastern and north-eastern networks were back on line. "I'm not going to start with a blame game. The centre and the states will have to work together on this," he added, as wary consumers who are used to regular load-shedding braced for the possibility of more serious disruption. Hundreds of miners were trapped underground for hours in the eastern states of West Bengal and Jharkhand on Tuesday, metro services were stopped temporarily in the capital New Delhi and hundreds of trains were held up nationwide. Traffic snarled in cities as traffic lights failed and hospitals and airports had to switch to back-up power. "On Monday the government said that this will never happen again but on Tuesday they proved themselves wrong. How can you trust them anymore?" said Revathi Nair, a 32-year-old manager with a five-star hotel in central Delhi. Former power minister Sushilkumar Shinde, who was promoted to home minister on Tuesday in a reshuffle announced in the midst of the crisis, said India should be more grateful for the efforts of its engineers and bureaucrats. "Where in America the grid doesn't get repaired for four days, here we repair the grid in several hours," he told reporters, repeating a boast that India had been more reactive than the US, which suffered a huge power failure in 2003. "You should appreciate us, the way work is done in the power ministry," he added. Wednesday's newspapers were predictably critical of the government, saying it lacked the political will to implement long called-for reforms in the power sector to boost production and sort out near-bankrupt state distributors. "Powerless and Clueless", ran the front-page headline in the Times of India, while the Economic Times splashed with "Superpower India, RIP" in a reference to New Delhi's bid to be recognised as a global economic and diplomatic force. On the streets of Delhi, small business owners seethed over the failures which caused computers to crash and expensive diesel generators to be called into action. "I spent over 2,000 rupees (about 40 dollars) yesterday just to buy diesel for my generator," said Ram Prasad Kejriwal who runs a shop selling shawls on a commercial street in the capital. "The entire day's sale was only 5,000 rupees." Business lobby group the Confederation of Indian Industry (CII) estimated the losses to small and large business in billions of rupees (tens of millions of dollars) and said India's investment image abroad had taken a major hit. The repeated outages "carry a very negative image of India, when already sentiments about the country are low on account of the current economic situation", CII director general Chandrajit Banerjee said in a statement. According to senior ministry officials, the two successive days of grid failure were triggered by energy-hungry states drawing power beyond their allocated limits. "We're facing power problems of Himalayan proportions," said Ajay Bodke, strategist at leading Indian investment house Prabhudas Lilladher. "Reforms can't wait any longer -- this is a wake-up call for immediate measures." Analysts say the power ministry needs to get state electricity boards to abide by their power quotas and manage distribution efficiently to avoid demand crunches. The finances of the distribution companies also need fixing by raising prices and cracking down on theft, which would allow them to invest more in their strained networks, they say. Finally, coal shortages are at the root of many of the problems because of the inefficiency of state-run giant Coal India Ltd (CIL), which is struggling to increase its production to meet the demand from power stations. India added 20,000 megawatts of power capacity in the past year -- enough to supply today's requirements, according to Alok Brara, publisher of the industry magazine Powerline. "But because of fuel issues they haven't been able to use the extra capacity," he told AFP.