M.Sc Maths

Hello,
I understand that you have interest to pursue M.Sc in Statistics. Kindly check the link mentioned below for the list of entrance examinations other than IIT JAM for M.Sc. Statistics:
http://entrance-exam.net/msc-in-statistics/
I hope this link answers your questions to your satisfaction. In case you have any further questions, kindly revert.

Yes, you can as the basic criteria is BE/ B.Tech/ M.Sc or equivalent and GATE score should be above 300 or qualifying score, whichever is higher.

Hi Nilesh,
It is better to pursue M.Tech as there is a great opportunity.

Source from IIT Delhi
Vision of the Department
The Department of Mathematics strives to be recognized for excellence among academic institutions in India and abroad. The Department wishes to focus on providing a comprehensive curriculum at undergraduate and postgraduate levels, relevant research and career opportunities in India and abroad.
Mission and Program Goals for the Next Decade
The Department plans to induct new faculty to enhance/strengthen the research as new faculties are a major source of new and fresh ideas in contemporary areas. The Department plans to start the Integrated M.Sc. + Ph.D. program.

You can do M.Sc in maths but if should be done in accordance with your Bachelor's degree.