Can you explain what the phrase "notwithstanding that it or parts of it may not be then in operation either at all or in particular areas" means in this context?
This phrase means that even if a law or part of it is not in operation at all, or only operates in certain areas, it will still be considered as "in force" under this article. The law or its parts may not be active or applicable everywhere, but they will still remain legally valid and recognized within the scope of this article.