Along with Air India and IndiGo, what Mumbai-based airline is in India's top three for passenger numbers?
Air India:  Additionally, the carrier is the third largest domestic airline in India in terms of passengers carried (after IndiGo and Jet Airways) with a market share of 13.5% as of July 2017. Jet Airways: Jet Airways (Hindi: जेट एयरवेज , "Jet Eyaravej") is a major Indian international airline based in Mumbai. Jet Airways:  In July 2017, it was the second largest airline in India after IndiGo with an 18.2% passenger market share.
Jet Airways