Two Air India pilots have reportedly failed mandatory drug tests launched after a recent in-flight incident that left passengers and crew members injured, Indian media reported on Monday.

Air India began conducting compulsory drug screenings for all of its more than 5,000 pilots at the airline and its subsidiary Air India Express from August 13.

Nearly 400 pilots have completed the tests so far, with two receiving "non-negative" results and awaiting further confirmation, according to a report by NDTV, citing sources.

The two pilots have been de-rostered as a precautionary measure, Air India said, adding that the decision was taken in the interest of flight safety.

The drug screening campaign was launched after Air India flight AI2379, flying from Phuket to New Delhi, suddenly dropped about 91 meters in altitude this month, injuring 24 people on board. The plane later landed safely.

A cabin crew member on the Phuket-Delhi flight is believed to have lodged a complaint alleging that the pilot had previously smoked marijuana.

The aircraft captain subsequently tested positive for marijuana in a drug screening, according to Indian authorities. The incident has triggered renewed scrutiny over aviation safety and pilot health checks in India.

Under regulations issued by India's Directorate General of Civil Aviation, a pilot who tests positive for psychoactive substances for the first time must go to a de-addiction or rehabilitation program. They can go back to flying work after they pass a new negative test and get a fitness nod.

A second positive result would lead to a three-year suspension of the pilot's license, while a third positive test would result in permanent cancellation of the license.