Hello student you can't get into ICMR after 12 as eligibility criteria says - M.D/PhD degree with at least three years teaching/research experience for young scientists and at least fifteen years for senior scientists
Regular position in a recognized biomedical/research/health institution in India

For more updates refer to refer to the link mentioned below - https://studyabroad.careers360.com/news/international-fellowships-biomedical-scientists-icmr

Feel free to comment if you have any doubt

Good luck