Hello.
For now nothing can be predicted, as it's  global crisis of pandemic so all the organisation are doing their best they are trying to take decision in the favour of their students and public, CBSE is thinking to organise examination, depending upon the condition this decision may vary but you don't need to bother, you can be prepared with the subjects that will really help you in your future if exam do not conduct and if they cancel so your entire percentage would be calculated on the basis of your rest subject marks or there may be another criteria.
Best of luck.