You can consider below names as these colleges are decent to pursue M.Sc in Maths -

1. IIT Kharagpur
2. IIT Bombay
3. IIT Delhi
4. IIT Guwahati
5. IIT Kanpur
6. Acharya Narendra Dev College
7. Madras Institute of Technology
8. ISM Dhanbad
9. BITS Pilani
10. Government Degree College Rajahmundry etc.

Good Luck!!!!