TIFR - Tata Institute of Fundamental Research Mumbai Answered Questions

There is no separate M.Sc program in mathematics at TIFR. TIFR - Mumbai offers integrated Ph.D programs in the School of Mathematics, TIFR - Mumbai. The eligibility criterion for admission to integrated Ph.D program is a Bachelor's degree in any of mathematics, statistics, science or Technology (BA, B.Sc, B.Mathematics, B.Statistics, BE or B.Tech).
Students with a four year Bachelor's degree may be considered for admission in Ph.D program. TIFR conducts entrance examination for admission to integrated Ph.D mathematics programs. The eligible candidates will have to first appear for a written screening test. Candidates who pass the screening test will be called to appear for an interview, which is the main part of the examination.

Hi
TIFR is an autonomous Research Institute under the Department of Atomic Energy, Government of India. It is also a Deemed University recognized by the University Grants Commission, offering Ph.D, Integrated M.Sc.-Ph.D, and M.Sc programs in physics, chemistry, biology, mathematics, computer science and science education. So for your B.Sc, you may apply to IISC through JEE.