Agenda 21 recommends that existing national, subregional, regional and international information systems should be developed and linked through regional clearing-houses covering broad-based sectors of the economy such as agriculture, industry and energy. Such a network might, [inter alia], include national, subregional and regional patent offices that are equipped to produce reports on state-of-the-art technology. The clearing-house networks would disseminate information on available technology, its sources environmental risks, and the broad terms under which it might be acquired. They would operate on an information-demand basis and focus on the information needs of the end-users. They would take into account the positive role and contribution of international, regional and subregional organizations, business communities, trade associations, non-governmental organizations, national governments and newly established or strengthened national networks.