Indigo aircradts parked at the Kempegpwda International Airport in Bengaluru.
India's largest airline IndiGo said on Wednesday that it has faced delays and cancellations in recent days due to technology issues, airport congestion and what it termed "operational requirements".
Roughly 40 IndiGo flights have been cancelled so far in Delhi on Wednesday, according to two airport sources.
The sources and an IndiGo pilot, all requesting confidentiality, said the airline was facing crew shortages, which two of them attributed to new pilot duty time limitations that took effect in recent months.
In total around 700 flights were delayed as of 3.30 pm on Wednesday across India's three busiest airports - Delhi, Mumbai and Bengaluru - with Delhi accounting for more than two-thirds of the delays, according to data from Flightradar24.
The disruptions follow an air traffic control system outage at India's capital airport that delayed hundreds of flights for several airlines last month.
More than 70 flights have been cancelled by IndiGo including those from Bengaluru and Mumbai airports, on Wednesday, due to crew shortages.
Scores of IndiGo flights were delayed at various airports, as the carrier struggled to get the crew for operating its flights, sources said.
An airline spokesperson said, "We have had several unavoidable flight delays and some cancellations in the past few days due to various reasons including technology issues, airport congestion, and operational requirements."
"IndiGo has been facing acute crew shortage since the implementation of the second phase of the FDTL norms, leading to cancellations and huge delays in its operations across the airports,” a source said.
"The situation turned bad on Tuesday for the airline and the shortage turned worse on Wednesday with scores of flights cancelled and delayed from across airports in the country," the source said.
At Bengaluru's Kempegowda International Airport, IndiGo cancelled 42 flights on Wednesday including 22 arrival and 20 departure flights.
The cancellations are due to operational reasons and a cascading effect of multiple delays, an IndiGo representative shared.
As per an airport source, arrivals from sectors such as Delhi, Hyderabad, Mumbai, Chennai, Goa, Kolkata and Lucknow were cancelled.
Among departure flights impacted are Mumbai, Delhi, Goa, Hyderabad, Chennai, Kolkata and Ahmedabad.
Twenty IndiGo flights were also cancelled at KIA on December 2. Passengers at the airport have complained about severe delays, between one to three hours, in IndiGo flights over the past week.
A chaotic situation unfolded at the Rajiv Gandhi International Airport after Indigo airlines cancelled 13 flights to various destinations, including Delhi and Bengaluru, airport sources said.
The airport said that some IndiGo flights have been impacted due to airline-related technology and operational issues, resulting in delays and cancellations.
Similarly, the airline also cancelled 18 incoming flights from various destinations, the sources said. Nine flights were cancelled on Tuesday alone.
(With PTI, Reuters and DHNS inputs)