Pinpointing exact reason not realistic, claims Indigo

Meanwhile, regulator, DGCA is probing the reasons behind the unprecedent meltdown at India's largest airline that has an almost 65% share in the domestic market.

The DGCA said IndiGo had requested a fortnight to conduct a comprehensive Root Cause Analysis (RCA) of the disruption. A preliminary explanation was submitted by the airline on Sunday evening, and the regulator is reviewing it before deciding on enforcement action.

IndiGo told the DGCA that pinpointing the exact causes of the disruption was "realistically not possible" at this stage due to the scale and complexity of operations. The airline cited the DGCA manual, which allows a 15-day response period for show-cause notices, as the basis for the extended timeline.

In its preliminary explanation, IndiGo attributed the disruptions to a combination of factors: minor technical glitches, schedule changes linked to the start of the winter season, adverse weather, increased congestion in the aviation system, and implementation of updated crew rostering rules under the Flight Duty Time Limitation Phase II.

The airline said these compounding factors caused a drop in on-time network performance, which in turn affected crew availability.

IndiGo reportedly took the "drastic measure" of rebooting its network ion December 5, by cancelling a significant number of flights to recover stranded passengers, ease airport congestion, and reposition crew and aircraft.

The airline expressed regret over the inconvenience caused to passengers, describing the disruption as the result of an "unfortunate and unforeseeable confluence" of multiple factors.