52 Therefore, it will be necessary that in each country the Bishops set up a permanent national reviewing office in order to be able to promote good motion pictures, classify the others, and bring this judgment to the knowledge of priests and faithful. It will be very proper to entrust this agency to the central organization of Catholic Action which is dependent on the Bishops. At all events, it must be clearly laid down that this service of information, in order to function organically and with efficiency, must be on a national basis and that it must be carried on by a single centre of responsibility. Should grave reasons really require it, the Bishops, in their own dioceses and through their diocesan reviewing committees, will be able to apply to the national list - which must use standards adaptable to the whole nation - such severer criterions as may be demanded by the character of the region, and they may even censor films which were admitted to the general list.
Source: Vigilanti Cura (Vatican.va)