It actually creates a lot of problems especially if you go for B school interviews or placement interviews. They're going to grill you about it but if you have a valid reason or you can concoct an answer that can convince others you'll easily get through. Don't worry students in developed countries take year breaks after school to learn about outside world before starting their career and that's normal there. People in India only have problems but that should not stop anyone from going higher. Work on creating an answer and it won't be an issue 

All the best 

Hey there

There is no rule that if you have 3 year gap then you will not be eligible for MBA or Mtech. But when you will go to the interview of top MBA colleges then they will definitely ask you the reason of the gap infact If one score less in 12th even then they ask the of low score. In Mtech there is less discussion about it but still again they will ask about the gap you should have a proper answer to the question with genuine reason. 

Good luck