The massive failure of power transmission lines that affected more than 60 crore (600 million) people in 21 states across the country today is the worst-ever in world history.

Today's power collapse is worst-ever in terms of number of people affected. The other big power outage recorded include the 2005 power crisis in Indonesia that impacted at least 10 crore (100 million) people due to grid issues.

Another major outage took place in 2009 when natural disaster devastated a hydel project on the border of Paraguay and Brazil, snapping power for about six crore (60 million) people.

A major power failure hit China in early 2008 had left around 0.4 crore (4 million) people without electricity.

Today's collapse was triggered by failure of three grids serving India's Northern, Eastern and North Eastern regions at 1300 hours today.

This happened less than 24 hours after supplies from the Northern Grid was restored after an outage on early Monday morning that affected over 30 crore (300 million).

Also, today's collapse hit the Talcher-Kolar HVDC (High Voltage Direct Current) transmission line, considered Asia's longest running from Orissa to Karnataka.

A Power Ministry official said India has one of the largest electricity networks in the world and the generation capacity is over 2 lakh MW.

The demand has been consistently growing and the peak hour deficiency is over 10 per cent, according to official data.

Interestingly, Eastern region has the biggest power infrastructure in the country having at least 25,000 MW generation capacity. Most of them are thermal plants since the area is abundant in coal resources.

Further, electricity generated from projects in this region caters to at least ten states in the country.