If I score 70% or less than that upto 65%, then am I eligible to get admission in any of the IITs??? I belong to general category. I am appearing in 12th improvement examination as a CBSE PRIVATE CANDIDATE.

dear anand 
sorry , if you are talking about class 12^th percentage , then you cannot with this mark . 
you need at least 75 percent to elligible for jee advanced councelling . 
and without jee advanced councelling you cannot enter into iit . 
hope it clears 
kindly approve 
regards