New Delhi, Dec. 5 -- India's aviation network has been plunged into disruption, with nearly half of all domestic flights cancelled over the past three days-largely at IndiGo-stranding hundreds of thousands of passengers and forcing the regulator to blink and soften its newly-tightened pilot fatigue norms. The Directorate General of Civil Aviation on Friday gave IndiGo time until 10 February to comply with limits on consecutive night operations, a pause the government says is essential to restore stability even as pilots and safety experts warn the move undermines hard-won fatigue protections.

The directorate had proposed to roll out two rules for all airlines. The first, which came into effect from 1 July asked airlines to give pilots we...