In December 2025, IndiGo — India's largest airline with over 60% domestic market share — experienced a severe scheduling crisis that led to the cancellation of approximately 4,500 flights between December 2 and 12, 2025, affecting lakhs of passengers. The root cause was the airline's failure to adapt its crew scheduling systems to the new Flight Duty Time Limitation (FDTL) rules mandated by the Directorate General of Civil Aviation (DGCA). These rules, announced in June 2024, increased mandatory pilot rest periods and imposed stricter night-duty restrictions. IndiGo and other carriers had lobbied against the changes and delayed implementation until 2025. On December 9, 2025, DGCA ordered IndiGo to cut 5% of its winter flight schedule — subsequently revised upward to 10% by the Ministry of Civil Aviation. A temporary exemption from certain FDTL provisions (notably night duty rules) was granted until February 10, 2026, with mandatory periodic reviews. IndiGo was directed to issue full refunds to affected passengers by the next day. The crisis highlighted India's aviation sector vulnerabilities — including thin pilot rosters, inadequate crew scheduling technology, and the friction between regulatory compliance timelines and airline operational readiness. Subsequently, DGCA imposed a penalty of ₹22.20 crore on IndiGo over the disruption.