The UMSRA management has added all the Category and Origin objects and wants to disable any further addition and deletion. They have asked you to disable ‘Add’ and ‘Delete’ buttons. You can do this by overriding the has_add_permission and has_delete_permission in the Django admin.:
def has_add_permission(self, request):
    return False

def has_delete_permission(self, request, obj=None):
    return False
With these changes, the admin looks like this
_images/remove_add_perms.png
Note the removed Add buttons. The add and delete buttons also get removed from the detail pages. You can also read How to remove the delete selected action in Django admin?.