Hello aspirant,

Here are list of top colleges for PhD in mathematics.

• Jamia millia islamia, New Delhi
• IIT Bombay
• Lpu jalandhar
• Christ church university, Bangalore
• Jadavpur university, Kolkata

And many more please visit this link for more college.

https://university.careers360.com/colleges/list-of-phd-in-mathematics-universities-in-india

Hope this helps you

Feel free to ask any questions

All the best for your future