Hello student,

See as per my knowledge, improvement examination is provided to improve your marks in subjects if you are not satisfied with your 10 plus two level marks in CBSE then only in the succeeding year you may can reappear in the examination.

Now you have total about 2 years gap. For this reason as per my knowledge you may cannot bi a and for improvement examination. But it will be better for you if you can contact with CBSE board authority from your own to have a clearity. Hope this will help you