The airlines consult IATA TIMATIC to decide if you’ll be allowed to fly or not because you meet - or don’t meet - the passport and visa criteria of your destination and transit countries. If you don’t have an Indian visa or passport that doesn’t require one you’ll never make it as far as the first aircraft.
You can use TIMATIC too. United provides a webform you can fill out that will tell you if you have requirements to fulfill here:
https://www.united.com/web/en-US/app...aspx?i=TIMATIC. (And many countries, including USA, China and India, iirc, consider your flight plans as requiring a visa.)