Dear Manish ,

The CBSE improvement exam is for students who have passed the board exam in the concerned subject and are keen on improving their score. Please note that students who have failed the subject in the board exams are not eligible to write the improvement exam. The CBSE improvement exam can be taken in one or more subjects .It will release soon but till now there is no official announcement for this so we should wait for that .

Hope it will helpful

thanks