India faced an embarrassing blackout on Tuesday, affecting half the population that covered 20 states in the North, East and North-East.

The Northern grid failed on Monday, causing complete blackout in Punjab, Haryana, Rajasthan, Delhi, Uttar Pradesh, Uttarakhand, Himachal Pradesh, J&K and Chandigarh.

The blackout spread to East and North-East on Tuesday after the Eastern, North Eastern grids failed. States that faced blackout are West Bengal, Chhattisgarh, Bihar, Jharkhand, Orissa, Sikkim, Arunachal Pradesh, Nagaland, Assam, Meghalaya, Manipur, Mizoram and Tripura.

Now, the big question is whether the blackout will spread to West and South India.

Well, it seems the collapse of the Northern grid almost affected Western India too as the Western grid is inter-connected to Northern, Easthern and North Eastern grids. Officials said that the region would have faced electricity problem if not for the timely intervention by the authorities.

A senior official from the Maharashtra State Electricity Distribution Company Limited (MahaVitaran) said with the collapse of the Northern grid affecting power generation from six sets of a total 1,500 MW capacity at the Vindhyachal power plant in Madhya Pradesh, from where Maharashtra has an around 500 MW quota, they had increased generation at the Koyna project by about 500 MW to make up for the loss of generation and match the power requirement, reported DNA.

"Otherwise, there would have been an effect on our grid which was averted," he told the daily.

States like Maharashtra, Madhya Pradesh, Goa, Gujarat and Chhattisgarh would have been affected if the Western grid failed.

However, South India is very unlikely to be affected by the current power grid failure in the country as the Southern grid is not inter-connected to the other grids. It is in fact supplying power to help restore electricity in the affected regions.

There are five electricity grids covering the whole country namely Northern, Eastern, North Eastern, Southern and Western. It is from these grids that power is distributed to the consumers.

Power failure on Monday and Tuesday disrupted the normal lives of the people and affected over 300 trains. The blackout also caused worries on the operation of hospitals in various cities.

"The Northern Region Grid was failed which provide Power Supply to 9 States of Northern India including Delhi. It was due to Grid disturbance that occurred at about 2.35 a.m on 30th July, 2012," said a statement on Power Grid Corporation of India website.

"Restoration work started immediately on war-footing under the direction of CEO, POSOCO and POWERGRID's Chairman & Managing Director. A team of engineers tried to find out the way for restoring the normal supply of power immediately so that at least priority areas like Railways, Metro, Airports & other essential load could get immediate power supply," it added.