His research interests are general relativity and cosmology. He has made fundamental contributions to black hole physics and gravitation theory. His extensive analysis of general relativistic gravitational collapse has been widely recognised for providing significant insights into the final fate of massive collapsing stars in the universe, the formation of space-time singularities, and cosmic censorship. Stephen Hawking invited Professor Joshi to Cambridge University, UK, in 1981 and 1986 to work with him under the Nuffield Foundation Fellowship. He has also been acclaimed by Dr APJ Abdul Kalam, Dr R Chidambaram, Dr Jayant Narlikar, and several such leaders in science, as an eminent scientist.