You need to have maths and physics as main subjects in your 12th class and, should have passed out.
Then search for your ideal flying school and get admitted there. You could complete the duration in 4 to 6 months.
Some free flying schools in India are :
- Asia Pacific flight academy, Telangana
- Flytech aviations, hyderabad
- Carver aviations, Maharashtra
- National flying academy, nagpur
- The Bombay flying club, Maharashtra
You need to become a Bchelor's degree in aircraft operations, aviation, aeronautical engineering or a related field. I addition, you will complete upto two months of ground training and more than 1500 hours of flight experience.
Hope it helps.