India, Dec. 7 -- The aviation regulator DGCA on Saturday issued a show cause notice to IndiGo chief executive Pieter Elbers, holding him directly accountable for "significant lapses in planning, oversight, and resource management" and giving him 24 hours to explain why enforcement action should not be initiated for violations that precipitated the country's worst aviation crisis in years.

The civil aviation ministry separately imposed emergency fare caps on domestic flights and ordered IndiGo to complete all refunds by Sunday evening, as tens of thousands of stranded passengers across Indian airports confronted surging ticket prices, missing luggage and mounting anger in the fifth day of the operational meltdown.

Fllow IndiGo flight can...