GATE (Graduate aptitude test in engineering) IIT conduct GATE once in a year in month of Jan.-Feb.
Eligibility : for mathematics(MA) - MSc in mathematics/M.E/M.Tech in related discipline
AGE : there is no bar on age
scholorship : 25000 for Ph.D
12000 for M.tech(computer science,industrial mathematics, information technology)
gate 2018 official link : http://gate.iitg.ac.in/