New Delhi, March 4 -- Clouds over vast swathes of North India have caused abrupt dips in solar power production, raising worries about the stability of the power grid that serves millions of Indians.

The national grid operator asked all electricity companies in February to be on alert mode and supply power to preserve the grid's stability, two people aware of the matter said.

"There have been instances of a dip in power generation, which puts the grid under strain. In mid-February, it went below the requisite range and hit 49.5 Hz, raising a concern. A balance needs to be made in terms of renewable energy and other sources power, mostly coal," one of the people mentioned above said on the condition of anonymity.

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