Dear Amulya
Majority of students pursue M.Tech degree after completing their undergraduate degree. Every year, more than 8 lakh candidates appear for Graduate Aptitude Test in Engineering (GATE) for M.Tech Admissions offered across IITs, NITs and other leading centrally funded institutes. Apart from the biggest PG engineering entrance exam in India, there are many other well-known private universities that hold their own entrance test for PG admissions. Most of the states accept GATE scores of candidates for M.Tech admissions, while some conduct entrance exams for the same.
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Hope, this helps.
All the best.