Complex sentence: At the time of his retirment from service in 2004, he was serving as the Dean of Research and post-retirement, he holds the Dr. C.G. Pandit National Chair of the Indian Council of Medical Research at AIIMS, continuing his research at the institution.
Split into simpler sentences: At the time of his retirement from service in 2004, he was serving as the Dean of Research and post-retirement. As of now, he holds the Dr. C.G. Pandit National Chair of the Indian Council of Medical Research at AIIMS, continuing his research at the institution.