Rail services came to a screeching halt as power tripped, affecting lakhs of passengers across northern India.
However, the situation was much better at Delhi's Indira Gandhi International Airport (IGIA) as only two flights were delayed due to power cuts.
Delhi International Airport Limited (DIAL), however claimed that there were no cancellations or delays.
"Entire load of the airport was restored within 15-60 seconds. As soon as the power supply showed fluctuations, the 'Main Receiving Sub-Station' (MRSS) at IGIA ensured that the DG sets automatically took the load," a DIAL spokesperson said.
But rail passengers were not that lucky since trains were reported stranded at almost every station in northern India when power went off in seven states at 2.33 am due to the major failure in northern grid.
Around 300 trains, including 130 of the Northern Railway division, were affected on their way to the Capital from several parts of the country, the railways said.
"Around 130 Northern Railway trains were affected due to grid failure. All trains were stranded as signals were not functional. It will take some time before trains services are restored fully as there is a huge backlog," said Niraj Sharma, chief PRO, Northern Railway.
Fifty trains, including several Rajdhani, Shatabdi and Duranto express, were rescheduled to clear the backlog. Some trains were pulled by diesel engines and brought to the Capital.
"To provide immediate relief to passengers, we replaced electric locomotives with diesel engines as the power failed," Sharma said.
All electric suburban trains have been cancelled till the time the backlog is cleared and complete supply is restored, officials said.
It was complete chaos at railway stations as thousands were stranded at several stations across Delhi.
Many complained that there was no information available about the arrival and departure timings of trains.