How many students are there in AIIMS Delhi who have dropped more than 2 or 3 years and are doing great at studies in AIIMS?

I cannot comment on how the students who dropped a few years are doing currently but yes I can tell you that there certainly are students who managed to make it into AIIMS even after taking drop years. This requires a lot of determination. 

Firstly, there is no certainty that taking a drop year will assure a seat the next year. In fact, going to the same syllabus once again is going to be tough and will take a toll on you. It is a courageous decision. Moreover, when you will look at your friends who have started their M.B.B.S. the sense of failure might take over you. For some, this might be a sense of motivation though. So it’s best to analyze if you are ready for the drop and the consequences.

Coming to real-life examples, I have some friends who have taken 3-4 years drop and made it into top medical colleges but not AIIMS. It was their hard work and dedication that made them stronger and not give up.

I suggest you not be adamant about AIIMS and keep all options open. That will not limit your opportunities and you will make it through somehow.