Air India tweeted that normal operations have resumed.
Soon after the Air India flights were delayed, people at the airport started tweeting.
"Just reached Delhi Airport and found out that Air India servers are down for the last two hours. All domestic and international flights are grounded. The airport looks like a mela of stranded passengers with hardly any space to even walk," chief executive of BlueKraft Digital Foundation Akhilesh Mishra tweeted.
Another Air India passenger, Manan Jain, tweeted with a photo of his plane seat of an Air India flight. "Waiting for Air India to depart for the last one hour inside the plane. No information no updates, just pure harassment," Mr Jain said.
Minister of State for Civil Aviation Jayant Sinha said they had been following up on the matter and the systems have now been restored." Apologies for the inconvenience suffered. Air India has been asked to ensure that our valued passengers are kept fully informed at all times," Mr Sinha tweeted.
Earlier this week, the government decided to cancel divestment in Air India. Since the airline has been posting operational profits, the government does not feel the need to rush for a stake sale, people familiar with the matter have said.
A 76 per cent stake of the debt-laden carrier was put on sale by the government in March this year, but on May 31, when the deadline for bidding ended, Air India did not get any interest from investors.
Get the latest election news, live updates and election schedule for Lok Sabha Elections 2019 on ndtv.com/elections. Like us on Facebook or follow us on Twitter and Instagram for updates from each of the 543 parliamentary seats for the 2019 Indian general elections. Election results will be out on May 23.