After a MSc. In Mathematics, you may go for a PhD in Mathematics, Modelling & Simulation, Computational Sciences, AI, Mathematics and Computing, Statistics & Data Science related areas, provided you have relevant interests and research experience. You may even go for a PhD in Mathematics and take up a Research Domain related to Technology, Mathematics and Data for the next 5 years.

For more information about PhD in Mathematics in Indian Universities do follow the link below

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