New Delhi, Dec. 6 -- The civil aviation regulator DGCA on Friday capitulated to IndiGo's demands and granted a one-time exemption from crew fatigue rules introduced last month, even as India's biggest airline cancelled over 1,000 flights-more than half its daily operations-in the most catastrophic day of a meltdown that has stranded tens of thousands of passengers across four days and led to angry scenes at airports. The Directorate General of Civil Aviation (DGCA) granted IndiGo relief from provisions limiting pilot duty hours at night until February 10, rules that were first announced in January 2024. The regulator insisted the exemption was granted "solely to facilitate operational stabilisation and in no way amounts to dilution of safety requirements" and it would monitor IndiGo's remedial measures as well as probe the reasons behind the disruptions. The exemptions extend well beyond the primary relief from night-time flight duty limitations. The regulator authorised IndiGo to redeploy pilots currently on deputation with DGCA as inspectors back to flying duties. Separately, it withdrew a rule that prevented airlines from counting pilot leave as weekly rest to meet flying duty norms. On Friday, the airline cancelled most, if not all, flights from some of India's busiest airports: Delhi, Chennai, Mumbai, Bengaluru and Hyderabad, in addition to 12 smaller airports, such as Kanpur, Itanagar, Deoghar and Khajuraho, where the airline is the sole medium-haul carrier. The airline, which commands 60% of India's domestic market, has now cancelled approximately 1,600 flights since Tuesday, when the crisis erupted into public view. IndiGo's chief executive Pieter Elbers admitted in a video message to customers that "earlier measures of the last few days have proven not to be enough". "So we decided today for a reboot of all our systems and schedules, resulting in the highest number of cancellations so far, but imperative for progressive improvements starting tomorrow onwards," Elbers said, adding that the airline expects cancellations to fall below 1,000 on Saturday. The company's on-time performance for Thursday, when roughly 300-400 flights were cancelled, stood at an abysmal 8.5%. The CEO said IndiGo anticipates returning to "a full normal situation" between December 10 and 15. "I do understand that these disruptions have caused much discomfort to our customers and has shaken their belief in IndiGo's reliability carefully built over past 19 years," he said. The Airline Pilots Association of India, which represents over 6,000 pilots, expressed "profound concern" over what it called "selective dispensations" to IndiGo, warning that the exemption "gravely compromised the safety of the flying public" and undermined the spirit of the Flight Duty Time Limitations. "Any dilution in FDTL norms would expose pilots, passengers, and aircraft to unacceptable risks," the association said. The regulator issued an appeal to all pilot associations "to extend full cooperation at the moment in view of the large scale demand due to winter holidays and marriage season". In an earlier letter to DGCA, the pilots' association alleged that despite the extensive preparation window, IndiGo "inexplicably adopted a hiring freeze, entered non-poaching arrangements, maintained a pilot pay freeze through cartel-like behaviour, and demonstrated other short-sighted planning practices". Anger spread among commuters as well. On social media, passengers shared videos of groups of people raising slogans against the airline. In one video, purportedly from Kochi airport, a passenger slammed the facade in front of the airline's counter, seething over being purportedly stranded for four days. Several videos on X and Instagram showed passengers accosting IndiGo staffers with demands for answer. Even the Singapore High Commissioner to India, Simon Wong, was trapped in the chaos, posting on X that his flight was cancelled and he was "lost for words" as he could not attend the wedding of a young staff member in the remote town of Deoghar, in eastern India. Compounding the airline's self-inflicted crisis, technical failures in IndiGo's crew-rostering and scheduling software have further paralysed operations, according to two officials who spoke to HT. The airline simultaneously grappled with malfunctioning baggage systems at Delhi's Terminal 1 and Terminal 3, with cascading delays in baggage delivery persisting through Friday. "The issue has led to mounting operational strain and increasing pressure on airport infrastructure and hence all the stakeholders have been asked to observe a vigil," one official said. Civil aviation minister Ram Mohan Naidu reviewed the situation through a 24x7 control room on Friday morning after a series of high-level meetings at the ministry. "We have formed a committee that will establish where things went wrong and who did it wrong. We will take the necessary action, so that whoever was responsible for this needs to pay for it," Naidu said. On Thursday, IndiGo had admitted to DGCA that the meltdown stemmed from misjudgment and planning gaps in adapting to regulations announced in January 2024. The airline acknowledged it failed to anticipate actual crew requirements under the revised norms and that "significant planning and assessment gaps existed in implementing Phase-II of FDTL", the DGCA stated on Thursday. The lack of preparation came even as the airline opted for aggressive capacity expansion. IndiGo's approved winter schedule for this season comprises 15,014 weekly departures-an average of 2,145 flights daily-representing a 9.6% increase over the previous winter when it operated 13,691 weekly flights. DGCA on Friday constituted a four-member committee to conduct an independent review of the operational breakdown, citing "deficiencies in internal oversight, operational preparedness, and compliance planning". The panel, headed by joint director general Sanjay K. Bramhane, will "identify accountabilities and responsibilities for failure" and submit findings within 15 days "to enable necessary regulatory enforcement action". The committee will examine underlying causes of the breakdown, assess adequacy of manpower planning and rostering systems, review FDTL compliance gaps, and evaluate whether IndiGo is taking adequate steps to restore operations....