India, Dec. 4 -- IndiGo cancelled at least 150 flights on Wednesday, triggering chaotic scenes at major airports across India as the carrier's struggles to adapt to stringent new crew rostering rules meant even minor operational disruptions snowballed into a full-blown crisis that stranded thousands of passengers.

The airline apologised for the crippling disruption and warned travellers to brace for further cancellations through Friday, saying it had initiated "calibrated adjustments" to stabilise operations over the next 48 hours.

"We acknowledge that IndiGo's operations have been significantly disrupted across the network for the past two days, and we sincerely apologise to our customers for the inconvenience caused," an airline spoke...