Wasim, 17, said a "middle-aged man" had repeatedly moved his foot up and down her neck and back while she was "half-asleep".

She documented the incident on Instagram and tried to film the man's behaviour but said it was too dark.

The airline, Air Vistara, said it was carrying out a detailed investigation into the incident. The airline said on Twitter that staff had not become aware of the incident until the plane was on its descent to Mumbai but it apologised for what Ms Wasim had experienced.

"We have zero tolerance for such behaviour," its statement added.

A suspect has been arrested, Indian media reports say, but his identity has not been disclosed.

Ms Wasim made her acting debut last year in Dangal, which became the top-grossing Bollywood movie of all time.