New Delhi, Dec. 5 -- At least 250 IndiGo flights were cancelled on Thursday as chaos continued at major airports across India, with the carrier struggling to adapt to stringent new crew rostering rules. On Wednesday, the airline cancelled at least 150 flights and announced that it had initiated "calibrated adjustments" to its schedules for the next 48 hours. The on-time performance (OTP) of IndiGo, India's largest airline, dropped to 19.7% on Wednesday from 35% a day earlier, according to civil aviation ministry data. An official aware of the matter said 33 flights were cancelled from Delhi, 68 from Hyderabad, 85 from Mumbai, and 73 from Bengaluru on Thursday. On Wednesday, at least 67 flights were cancelled at Delhi airport (37 departures and 30 arrivals), 42 at Bengaluru, 40 at Hyderabad (19 departures and 21 arrivals), and 33 at Mumbai (17 departures and 16 arrivals). In a statement on Wednesday, IndiGo said calibrated adjustments will remain in place for the next 48 hours and will normalise operations and progressively recover punctuality across the network. "Our teams are working around the clock to ease customer discomfort and ensure operations stabilize as quickly as possible." The airline said the affected customers are being offered alternate travel arrangements to reach their destinations or refunds, as applicable. The airline did not issue an update on its flight operations on Thursday. Technology glitches, adverse weather, increased congestion, and the implementation of updated Flight Duty Time Limitations (FDTL) that came into force in November triggered the chaos. An emergency Airbus A320 software patch rushed through over the weekend of November 29-30 disrupted crew scheduling just as the airline was operating with minimal slack due to the FDTL rules. The Directorate General of Civil Aviation (DGCA) data showed the airline had been under strain, having cancelled 1,232 flights in November-755 of them attributed to FDTL issues-with OTP dropping to 67.70% from 84.1% in October. IndiGo's baggage systems at Delhi's Terminal 1 and Terminal 3 encountered problems on Wednesday, compounding the aviation chaos....