Yes, but a handful of conventional missiles going back and forth against symbolic targets is not a very useful definition of a war, much less a world war, if for no other reason than it is to broad to be useful. The on again/off again three way between India/China/Pakistan comes to mind, as might India and Canada if the definition goes much beyond that. The word war tends to imply that nations don’t have active trade between them for instance, and generally implies that at least one side is attempting to achieve some sort of military victory.