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.

Definicija: Public utilities (or just utilities) are industrial organizations which provide the public with services such as water, gas, electricity, etc.: such undertakings are usually monopolies and, in many countries, are under state ownership or control.