what will happen in josaa counselling if any aspirant will not able to give central obc certificate rather provides state obc certificate ??

Hello,

For JOSSA counseling you're supposed to provide your central OBC certificate not your state OBC certificate.
It is clearly mentioned that if a candidate fails to provide a valid category certificate at the time of document verification, the candidate will be required to change his category to the category for which he has a certificate, else he will be considered a part of the General Category.
So if you provide a state category certificate it won't be considered and thus you'll be allotted seats based on general category.