Pollution is the introduction of contaminants into an environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms. Pollution can take the form of chemical substances or energy, such as noise, heat, or light. Pollutants, the elements of pollution, can be foreign substances or energies, or naturally occurring; when naturally occurring, they are considered contaminants when they exceed natural levels. Pollution is often classed as point source or nonpoint source pollution.
The Blacksmith Institute issues annually a list of the world’s worst polluted places. In the 2007 issues the ten top nominees are located in Azerbaijan, China, India, Peru, Russia, Ukraine and Zambia. In the late industrial age, the term overpollution was common, representing a view that was both critical of industrial pollution, but likewise accepted a certain degree of pollution as nominal industrial practice. Ancient cultures Air pollution has always been with us. Soot found on ceilings of prehistoric caves provides evidence of the high levels of pollution associated with inadequate ventilation of open fires.
The forging of metals appears to be a key turning point in the creation of significant air pollution levels outside the home. Core samples of glaciers in Greenland indicate increases in pollution associated with Greek, Roman and Chinese metal production.
Official acknowledgement The earliest known writings concerned with pollution were written between the 9th and 13th centuries by Persian scientists such as Muhammad ibn Zakariya Razi (Rhazes), Ibn Sina (Avicenna), and al-Masihi or were Arabic medical treatises written by physicians such as al-Kindi (Alkindus), Qusta ibn Luqa (Costa ben Luca), Ibn Al-Jazzar, al-Tamimi, Ali ibn Ridwan, Ibn Jumay, Isaac Israeli ben Solomon, Abd-el-latif, Ibn al-Quff, and Ibn al-Nafis. Their works covered a number of subjects related to pollution such as air.