For basic sciences, it’s difficult to choose between NISER Bhubaneswar and UM-DAE CBS. Both institutes have their advantages.
NISER has great faculty, laboratories, coursework. The campus of the institute is well-equipped and is spread over 3000 acres.
UM-DAE CBS has most of the visiting faculties from TIFR, Mumbai. Also, as it is located at the heart of Mumbai you will have better exposure. You can do your project from places like TIFR, BARC, IIT Bombay, etc.