B.Tech Scope

Dear Rithik,
Both are hard to achieve. For IIT (preferably top IITs) requires you to score 'good' marks in GATE with good number of work experience. And still you may find yourself suffering because of lesser number of seats and reservations. And for abroad, you need; #1) Lots of funds (if you didn't get the scholarships), hectic regulatory requirements, good number of work experience, exceptional academics and global competition. So, identify your potential and then go ahead. I would advise you to apply on both (I. e. , IITs and abroad). And where ever you get the chance, just grab it.
Hope this helps. Upvote the answer if you feel satisfied. Good luck.

Admission procedure & requirement: You have to give GATE or GRE (in some cases). For the cut-offs, you can check the colleges' websites. And if selected on the basis of GATE score, then they'll conduct an interview or a written test. The interviews are quite tough. Usually, the intake is very low. One of my friends got selected at IISc, Bangalore in Mechanical Engineering department. He said only 3 students were selected for M.Sc program. The situation is a bit better at IIT Chennai. They selected about 22 students out of 100 in Aerospace Engineering. department. Actually, the intake is dependent on the faculty's requirement. They also consider your GPA and projects. Students are admitted twice in a year. So the system is pretty much similar to the US graduation admissions.