The principle of efficient use of resources states that humans must value resources at their true worth and learn to use them frugally. This includes not exploiting renewable resources more rapidly than they can replenish themselves, counting the true costs of depleting nonrenewable resources, and requiring that those who cause pollution pay to clean it up. Under the principle of efficient use, emphasis is given to reducing consumption, recycling and reuse of products, and recovering of resources.
This strategy features in the framework of Agenda 21 as formulated at UNCED (Rio de Janeiro, 1992), now coordinated by the United Nations Commission on Sustainable Development and implemented through national and local authorities.