Hi,

You can get enrolled in NCC in other college/University  affiliated with a NCC unit.  Nearly all the colleges which have NCC in it give admission to the students of other college. So your work is to keep a check when the college is going to admit new cadets and get yourself registered and go through the selection process and if you are fit enough then you can join as an open cadet in that college's NCC. Also, You can look out for the Group Headquarters of NCC in your state.

Hope this helps.

Good luck.