Engineering

If you want to join the NDA then just an intermediate (10+2) in science is enough (Physics, Chemistry and Mathematics are must). If you are interested to join as an officer in a combat role (pilot/ground staff) after graduation, then a background and graduation in Science will suffice (even a B.Sc. Is enough). Apart from that, engineers from all fields and specialisations join as officers. If you want to join as an officer in the technical arms, engineers are chosen primarily from Mechanical, Electrical, Electronics, Civil and Aeronautical/Aerospace fields. However, in the written tests and SSB thereafter, if you show technical accumen and the right qualities, they'll definitely select you (remember, good officer material is hard to come by these days, explaining the fact that there is such a shortage of officers in the forces), even if your academic/educational background isn't the field they're recruiting for currently, and they wouldn't want to miss out on a good chap. Further, if you want to join the technical wing/ground staff roster as a JCO, you'll again need to give written exams, which will be a tad less stringent. Again, the fields of engineering are mentioned above. Most of the information about joining/commission is available in the Indian Air Force's official website.