Hi Parth,
The improvement examination is an examination that is conducted by the respective academic boards for students who wish to improve their class X or XII examination. This examination is conducted only once in the successive year of appearing for the exam in which you wish to appear for improvement. For example, you have appeared for your boards in 2018 then you would be able to give the improvement examination only in the successive year, i.e., 2019 and not any later.
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Hi Parth,

Please specify the exam name so we could assist you further.