Passengers flying IndiGo faced long queues across airports on Monday morning after the airline's server collapsed.
"Our systems have been down across the network since morning. As a result, we are expecting our operations to be impacted across the airports. All efforts are being made to resolve the issue at the earliest," the airline said in a statement.
The largest carrier by fleet size and market share, IndiGo said it was proactively informing passengers about the situation.
The airline offers close to 1,500 daily flights and connects 60 domestic destinations and 23 international destinations. It has a fleet of around 245 aircraft.
Carrying 55.5 lakh passengers in September 2019, it almost flew every second air passenger in the domestic market.
However, the airline's troubles have been mounting over the last few days. The aviation regulator Directorate General of Civil Aviation (DGCA) last week asked IndiGo to replace all its faulty engines powering the planes in the wake of frequent glitches reported in its Pratt & Whitney engines.
Failing to comply with the DGCA order, the low-cost carrier faces the risk of its aircraft being grounded.