Definicija: set up in 1947 by ECOSOC. It is one of five regional commissions of the United Nations. The others are the Economic and Social Commission for Asia and the Pacific (ESCAP), the Economic Commission for Latin America and the Caribbean (ECLAC), the Economic Commission for Africa (ECA) and the Economic and Social Commission for Western Asia (ESCWA). Its major aim is to promote pan-European economic integration. To do so, UNECE brings together 56 countries located in the European Union, non-EU Western and Eastern Europe, South-East Europe and Commonwealth of Independent States (CIS) and North America.

Definicija: Human settlements have an adverse impact on many ecosystems and on themselves by the addition of toxic or harmful substances to the outer lithosphere, hydrosphere, and atmosphere. The major types of environmental pollutants are sewage, trace metals, petroleum hydrocarbons, synthetic organic compounds, and gaseous emissions. Most, if not all, of the additions of potentially harmful substances to the environment are result of the population growth and the technological advances of industrial societies.

Definicija: Naselja ljudi, ki prispevajo toksične ali škodljive snovi v zunanjo litosfero, hidrosfero in atmosfero, slabo vplivajo na številne ekosisteme in tudi na njih same. Poglavitne vrste onesnaževal okolja so odplake, redke kovine, naftni ogljikovodiki, sintetične organske spojine in emisije plinov. Večina, če ne celo vsa, povečanja potencialno škodljivih snovi v okolje so posledica rasti števila prebivalstva in tehnološkega napredka industrijske družbe.