Hi Satyam,

Yes you can appear for the improvement exam but be well versed with its eligibility criteria as well. A candidate has to secure passing marks in his or her actual board exam and  candidate who wants to give the CBSE improvement exam cannot engage or cannot pursue any of the other higher studies, he/she will not be eligible for the improvement exam, he/she should be a dropper for that current year in which he/she is pursuing the improvement exam.