The National Defence Academy (NDA) is a joint services academy for the Indian Armed Forces, where cadets from the Army, Navy, and Air Force train together. Applicants must pass a written examination conducted by UPSC, followed by interviews, with about 300-350 cadets accepted each semester, and specific eligibility requirements based on nationality, age, sex, and educational qualifications. The application process includes a fee, and successful candidates undergo a two-stage selection procedure for final merit-based admission.