Sir/Madam,I got interview letter from IIT khargpur for M.Tech in Control Systems Engineering.

Hi rajitha,  since you have an interview call for mtech,  I suggest you prepare diligently for the interview irrespective of what your gate score is. Remember there are people who would give anything to be in your place to have a chance at the interview. You have to believe in yourself and go for the interview. By going you would atleast have a chance of getting in. But by not going you have taken away some one else's chance of getting an interview call and not done anything of it. It all depends on your interview. They don't call you for no reason. They don't have time to go through a candidate's interview just to reject them. So go and give the interview. Even if it is far from your home.