hi,

see cutoff score fluctuate every year and it depends on some of the facts i.e students category, choice of stream, number of applicants, choice of papers and so on. admission to iits in phd program is based on gate / ugc net scores, with follows by screening of academic record and interview. however at this score it would be really difficult to crack iits since you belongs to general category. however you may apply for jamia milia, university of hyderabad, maipal university jaipur, jadavpur university . follow the below link to know about colleges which offer phd in mathematics:

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

To know about complete list of probable college name, based on your score, category please use Careers360 college predictor tool,

https://engineering.careers360.com/gate-college-predictor?icn=QnA&ici=qna_answer