Northern India was hit by one of the worst power failures in a decade that saw millions wake up on Monday to no electricity. Rail, Metro and road-traffic operations, as well as services at hospitals and civic bodies, were severely disrupted.
Seven states in north India saw power trip off at 2.32am on Monday due to a major breakdown in the Northern Grid - an interconnected transmission network that delivers electricity from various power generating stations to distribution utilities.
The last time such a crisis took place was in 2001, when it took 16 hours to restore normalcy.
Apart from the national capital Delhi, supplies were badly affected in Punjab, Haryana, Himachal Pradesh, Uttar Pradesh, Rajasthan and Jammu and Kashmir, said VV Sharma, general manager of Power System Operation Corp Ltd.
The power failure also hit water supply with water treatment plants unable to operate.
By evening, the electricity supply was "almost fully restored", Sharma told IANS.
The power trip had occurred near Agra, the city of the Taj Mahal, but officials were unable to say what caused the massive breakdown.
"The reason is yet to be ascertained," said Sharma, adding that a three-member committee formed to probe the cause would suggest remedial measures.
The company, a subsidiary of the state-run Power Grid Corporation of India, which manages the grid, got power supply from the western and eastern regions, as also Bhutan.
The Northern Grid supplies power to nine states and at this time of the year, requires around 34,000-35,000 MW, said Sharma.
The power trip left many trains stranded in north India and saw thousands of early morning passengers of the Delhi Metro, including college and school students, crowd stations waiting for train services to start.
Power to the railways and Delhi Metro was restored by 9 a.m.
According to the company, parts of Badarpur in south Delhi, Narora and Simbhauli in Uttar Pradesh and Bhinma in Rajasthan were not affected by the tripping.
By afternoon, a semblance of normalcy was restored with most areas in north India getting electricity supply.
"It was such a relief to get the electricity back. We immediately put on the water pump as there was no water in the house," said Sharda Gupta, a housewife in Rohini.
Union power minister Sushil Kumar Shinde denied that essential services were hit.
Delhi Power Minister Harun Yusuf accused neighbouring states of Uttar Pradesh, Punjab and Haryana of overdrawing power which he said led to the collapse.
A Delhi Metro official said they received hydel power from Bhutan on a priority basis, and added that Delhi Metro was amongst the emergency services, including the Prime Minister's residence and the All India Institute of Medical Sciences (AIIMS), that were provided power.
"We have no clue on what is happening at the moment. Nobody actually knows about it. There is power failure in north India and the government is not concerned about what is happening around. Everybody is worried. This is what the Central Government is doing," said Vijay Kaul, a commuter.
"I have to go home. But they are saying that the metro is closed. We are really troubled," added another commuter.
Usha, a software engineer, said she waited for more than 30 minutes at Rithala Metro Station to board a Metro train.
"First I heard that trains will not run.However, I managed to get a train. But the train was slow and it took more than an hour for me to reach Kashmere Gate Station," she said.
The power failure also led to a majority of traffic signals not working in most areas, causing massive traffic jams during office hours. However, traffic policemen were seen at many intersections in the national capital manning the morning traffic.
According to a Northern Railway spokesperson, nearly 100 trains were disrupted. Many important trains like the Lucknow-Delhi Mail and overnight trains plying between New Delhi, Lucknow, Allahabad and Varanasi, Moradabad, were stranded en-route.
Many of the trains were brought to the nearest stations by diesel engines, a railway official said in Lucknow.
Railway traffic was back to normal by 8am. Around 45 local trains in Delhi were also affected.
Delhi's Indira Gandhi International Airport functioned normally with the help of generators.
"As soon as there was a disruption in power supply, all our essential services like flight arrival and departure, check-in, baggage handling, aerobridge services were shifted to our back-up system. So all these operations remained normal," an airport spokesperson said.
"We have one of the best DG (Diesel Generating) back-up system of the world. However, there might be some disruption in our non-essential services," he added.
There were reports of air conditioning not functioning in Terminal 1D and some portions of Terminal 3. Also, there was no power in some retail outlets at the airport.
"Overall 95% of our services remained unaffected," a spokesperson said.
The blackout also severely hit business activities. Chandrajit Banerjee, director general of Confederation of Indian Industry (CII), termed it "extremely unfortunate" and said the government must push reforms in the power sector and ensure adequate supply of coal to thermal plants.
The Associated Chambers of Commerce and Industry (Assocham) said the blackout had "severely impacted" business activities.
All government hospitals were put on emergency services and generator back-up, an official said.
Hydro-power generation in Himachal Pradesh resumed on Monday morning more than seven hours after the Northern Grid collapsed and stopped electricity production.
Twitter was abuzz as soon as the northern grid failed. The twitterati was tweeting about the blackout, helping with car pools, venting ire and one even looked for a Batman to save Delhi!
Here are a few samples: