New Delhi, April 21 -- Flight operations at Delhi's Indira Gandhi International Airport remained hobbled on Sunday, with roughly 68% of all arrivals and departures delayed, as the airport operator said airlines failed to heed warnings about disruptions issued four months ago and neglected to adjust their flight schedules.

Officials pinned the chaos on a combination of poor planning and months-long miscommunication, with one of the airport's four runways shut for upgrades during the busy summer travel season, coupled with an untimely change in wind direction - a perfect storm of factors that slashed capacity and left passengers blind-sided.

Delhi International Airport Ltd (DIAL), the airport operator, said airlines were informed about th...