The most apt session would be July 2022 session for you. If you take up July session, its the closest one for you. AIIMS conducts its PG exam for its admissions in 2 sessions i.e. January and July session. For being eligible for July session, you should have completed your Internship by December 31st of the same year. For example, if you want to appear for July 2022 session, you should be atleast completing your Internship by December 31st, 2022. Now if you want to appear for January session, you should have completed your Internship by January 31st of the same year of admission. So if you will complete your Internship by March 2022, you should appear for July 2022 session of AIIMS PG exam.