Transport Canada has asked Air India to investigate an incident in which a pilot was removed from a Vancouver-bound flight after being found under the influence of alcohol, according to a person familiar with the matter.

The pilot, scheduled to fly from Vancouver to Delhi on December 23, failed two breathalyzer tests conducted by Canadian police at Vancouver International Airport, which indicated they were unfit for duty. Transport Canada described the incident as a “serious matter” in a letter to the airline, and authorities may pursue enforcement action.

Air India confirmed the flight was delayed due to the incident and an alternate pilot operated the aircraft, a Boeing 777 with a capacity of up to 344 passengers. The airline said the pilot has been temporarily removed from flying duties while the investigation is ongoing and reaffirmed its zero-tolerance policy on regulatory violations.

“Pending the outcome of the investigation, any confirmed violation will attract strict disciplinary action in line with company policy,” the airline said.

Transport Canada’s letter, signed by official Ajit Oommen, requests Air India’s findings and details of preventive measures by January 26.

The incident comes amid heightened scrutiny of Air India’s operations following the June 12 crash of a Boeing Dreamliner that killed 260 people. India’s aviation regulator, the Directorate General of Civil Aviation (DGCA), has recently flagged multiple safety lapses at the airline, including notices this week to four pilots over alleged regulatory violations and safety concerns.

Regulations governing alcohol consumption for pilots differ between countries. Canadian law prohibits pilots from operating an aircraft within 12 hours of consuming alcohol, while India currently requires post-flight breathalyzer tests at the first port of landing. Proposed DGCA rules could make a pilot permanently lose their license after three positive alcohol tests.