Normal life was thrown out of gear when a power outage resulted in a blackout in 20 states across north, eastern and north-eastern India, affecting more than 600 million people for two consecutive days and severely disrupting essential services, including the country's water supply, industrial power supply, rail and road traffic management systems, and medical care.

The collapse of the northern grid affected Delhi, Punjab, Jammu and Kashmir, Himachal Pradesh, Haryana, Uttar Pradesh, Rajasthan, Uttarakhand and some parts of Madhya Pradesh while the failure in the Eastern Grid caused a blackout in West Bengal, Odisha, Jharkhand and Bihar. The northeastern states of Sikkim, Assam, Mizoram, Manipur, Nagaland, Meghalaya and Arunachal Pradesh were also plunged into darkness by the massive outage.

The three power grids collapsed at 1:05 p.m. local time Tuesday, and electricity was gradually restored during the course of the day. The multiple grid failure hit just as northern India was recovering from a blackout following the collapse of the northern power grid late Sunday night.

The outage led to 265 miners getting trapped in coal mines in West Bengal and Jharkhand, but they were rescued several hours later.

The power was fully restored to the three electricity grids overnight Tuesday by engineers from the Power System Operation Corporation (PSOC), the state-owned company that manages the country's electricity generation system.

The government has announced an investigation into the cause of the crisis, even as it was reported that the Power Minister, Sushil Kumar Shinde, was being promoted to the Home Ministry, causing an uproar.

Many Indians took to Twitter to express outrage, with some tweets reeking of sarcasm.

Sidin Vadukut, an Indian columnist tweeted: "We may not have electricity, but as a nation we have _____ (6 marks)"

A teacher and blogger, Dinesh Ghodke, wrote: "Power-cut in North India: When the dark night rises, its perfect time 4StarGazing... Come out armed with a telescope or iPad app StarWalk"

A blogger from Noida, Frootifer Vajpayee, wrote: "The awkward moment when you have Internet access and no electricity at home. Can't decide if it's a 1st world or a 3rd world country"

A user with an account named Internet Hindus: "We prevent 99% of power failures. Only 1% manages to get away with power-cut for entire north India - Owl"

Ram Viswanathan, a blogger: "India experiences the worst power outage in history and the minister in-charge gets a promotion :-)"

The Twitterati did not spare India's Congress-led ruling coalition UPA (United Progressive Alliance) Chairperson Sonia Gandhi either, following accusations that Shinde was being rewarded for his loyalty toward her.

Twitter user Amit Srivastava wrote: "Sonia Gandhi to her ministers: 'As much as u trouble Indians, I will reward u! Look at Shinde, he blacked out India, I made him Home Minister'"

Click 'Start' for a glimpse of how citizens coped with the blackout in northern and eastern India.

A teacher conducts a class for students under the light of kerosene lamps and a candle during a power outage inside a house in Kolkata, India, on July 31, 2012.

Commuters work on their laptops as they wait at a bus stop during a power outage at Noida, India, on July 31, 2012.

Vegetable vendors wait for customers at their stall during a power outage on July 31, 2012.

A gas oven mechanic waits for customers in his shop during a power outage in Kolkata, India, on July 31, 2012.

A customer holds a candle as he gets his hair cut at a barbershop during a power outage in Kolkata, India, on July 31, 2012.

Heavy traffic moves along a busy road during a power outage at the traffic light junctions in New Delhi, India, on July 31, 2012.

An officer reads documents with the help of a torch at the driving registration and license authority office during a power outage in Chandigarh, India, on July 31, 2012.

Employees manually fill containers with diesel during a power outage at a fuel station in New Delhi, India, on July 31, 2012.

Muslim girls study in the light of candles inside a madrasa or religious school during the power outage in Noida on the outskirts of New Delhi, India, on July 31, 2012.

People stand inside the driving registration and license authority office during the power outage in Chandigarh, India, on July 31, 2012.