New Delhi/Mumbai (PTI): The government plans to take strict action against IndiGo to "set an example" for airlines that violate regulations, the Civil Aviation Minister said on Monday, as the country's largest carrier added more flights as its operations limp back to normalcy following a week of widespread flight cancellations.

IndiGo, whose delayed preparation for stricter pilot rest rules triggered last week's wave of cancellations, operated 1,800 flights on Monday, up from around 1,650 on Sunday. At the peak of disruptions, more than two-thirds of its roughly 2,300 daily flights were grounded on December 5.

The sector regulator Directorate General of Civil Aviation (DGCA), which had previously issued a show cause notice to IndiGo CEO to explain the disruptions, set up a four-member panel to probe the matter.

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IndiGo CEO Pieter Elbers and COO Isidre Porqueras filed a "comprehensive" reply to DGCA show cause notices before the extended deadline expired on Monday evening, airline sources said.

IndiGo did not reply to an email sent for comments.

Meanwhile, a DGCA statement said it has received IndiGo's response to its show cause notice.

IndiGo, the statement said, is "profusely" apologetic and deeply regrets the inconvenience and hardship caused to customers.

The regulator also said that it is in the process of examining IndiGo's response and will take appropriate enforcement action.

The DGCA panel will assess manpower planning, fluctuating rostering system and airline's preparedness to implement the latest duty period and rest norms of pilots, sources said, adding that Elbers and Porqueras have been asked to appear before it on December 10.

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It will also review the extent of compliance of the Flight Duty Time Limitation (FDTL) rules, which were communicated to the industry more than a year in advance. It would analyse gaps as well as fix accountability.

Following mass cancellations, the government had given a temporary exemption from the rules until February 10, 2026.

The Phase 2 FDTL regulations, introduced on November 1, 2025, classify any duty between midnight and 6 am as night duty and reduce permissible landings within 24 hours from six to two or three. While intended to improve safety and manage crew fatigue, the rules are among the strictest globally.

Without additional hiring in the ultra-optimised airline, the new rules led to pilot shortages for IndiGo, which controls over 65 per cent market share. Tens of thousands of passengers were stranded as IndiGo's flight cancellations upended vacation plans and weddings, sparking growing anger over delays and lost luggage.

"We are not taking this situation lightly. We are doing an inquiry and will take very, very strict action... we will set an example for all the other airlines," Civil Aviation Minister Ram Mohan Naidu said in reply to questions in the Rajya Sabha.

While he did not elaborate on the action, Moody's Ratings said the airline could face potential penalties.

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"The disruptions are credit negative because IndiGo could face significant financial damage from loss of revenue because of flight cancellations, refunds and other compensation to affected customers, along with potential penalties imposed by DGCA," Moody's said.

In signs of the size of disruptions, the government said 5,86,705 IndiGo tickets were cancelled between December 1 and 7, with refunds amounting to Rs 569.65 crore issued to affected passengers.

A total of 9,55,591 tickets were cancelled between November 21 and December 7, and Rs 827 crore was refunded.

"After the recent disruptions, IndiGo has recorded considerable and consistent improvement across the network. Today, we are all set to operate over 1,800 flights, connecting all stations that we operate to," IndiGo said in a statement.

"We have optimised our operations and managed to reduce the number of cancellations, which are being notified to customers in advance, and our on-time performance (OTP) has also improved to 91 per cent across the network."

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On Monday, IndiGo cancelled over 500 flights.

The airline said it has delivered over 4,500 bags, which were checked in before the cancellations were announced, to passengers and would do so for the remaining equal number in the next 36 hours.

"We would like to reiterate that all our operations are fully compliant with the relevant FDTL norms and safety regulations, as they have been throughout the last two decades. We continue to work in full cooperation with the authorities to restore normalcy in operations," it said.

On Monday, IndiGo shares fell over 8 per cent - its biggest plunge since February 2022 - and marked a seventh day of selling that's cumulatively slashed USD 4.5 billion from the company's market value.

Shares of rival SpiceJet rose 5 per cent.