Announced in January, the rules increased flight crews' weekly rest periods to 48 hours from 36 and cut pilots' night flight duty times to a maximum of 10 hours from 13.

In Tuesday's revised website notice, however, the Directorate General of Civil Aviation (DGCA) allowed airlines to retain the older norms for the time being. The changes followed a review of data on pilot fatigue drawn from spot checks and airline surveillance after an IndiGo pilot collapsed and died in August before his flight.

(Reporting by Rama Venkat in Bengaluru; Editing by Clarence Fernandez)