The huge outage, said to have hit more than 600 million customers, shut down much of the northern part of the country's public transportation systems and forced hospitals, airports and other critical infrastructure firms to switch to backup generators for electricity. But it seems the were largely spared a major hit.

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Part of the reason the companies were not impacted is that most of their services and development operations are in western and southern India, which were not affected by the power cuts.

, for example, has its sales and marketing office in northern India but its software development and services facilities are mainly in Hyderabad and Bangalore in the south.

"We were not affected except for some inconvenience for the employees," said a spokeswoman for Microsoft in India.