Discrimination against refugees is prohibited on the additional grounds of membership of a particular social group, nationality, or political opinion. These grounds were absent in the 1951 Refugee Convention. Any refugee who has “committed a serious non-political crime outside his country of refuge after his admission to that country as a refugee” or who "acts contrary to the purposes and principles of the OAU" will be excluded from the definition.[3] It also contains a prohibition for refugees and asylum seekers to engage in any subversive activities against any member states.