The "Agenda – 21" of Rio Summit, 1992 is related to –

Agenda 21 is a comprehensive, non-binding action plan adopted by more than 178 governments at the United Nations Conference on Environment and Development (UNCED), also known as the Rio Summit or Earth Summit, held in Rio de Janeiro, Brazil, in 1992. The "21" refers to the 21st century.

Its primary objective is to achieve global sustainable development by addressing environmental degradation, poverty, and social inequality. It provides a blueprint for local, national, and global actions to ensure that development meets the needs of the present without compromising future generations. While the Rio Declaration included principles like the "Polluter Pays" principle, Agenda 21 specifically serves as the operational program for sustainability. The preservation of the ozone layer is primarily governed by the Montreal Protocol (1987).