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Litter on the coast of Guyana

Pollution is the introduction of

contaminants into the natural environment that cause adverse change.[1] Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants
, the components of pollution, can be either foreign substances/energies or naturally occurring contaminants.

Although environmental pollution can be caused by natural events, the word pollution generally implies that the contaminants

agricultural runoff

Many sources of pollution were unregulated parts of industrialization during the 19th and 20th centuries until the emergence of environmental regulation and pollution policy in the later half of the 20th century. Sites where historically polluting industries released persistent pollutants may have legacy pollution long after the source of the pollution is stopped. Major forms of pollution include air pollution, light pollution, litter, noise pollution, plastic pollution, soil contamination, radioactive contamination, thermal pollution, visual pollution, and water pollution.

Pollution has widespread consequence on human and environmental health, having systematic impact on social and economic systems. In 2015, pollution killed nine million people worldwide (one in six deaths).

Global South

Because of the impacts of these chemicals, local, country and international policy have increasingly sought to regulate pollutants, resulting in increasing air and water quality standards, alongside regulation of specific waste streams. Regional and national policy is typically supervised by

environmental agencies or ministries, while international efforts are coordinated by the UN Environmental Program and other treaty bodies. Pollution mitigation is an important part of all of the Sustainable Development Goals.[11]

Definitions and types

Various definitions of pollution exist, which may or may not recognize certain types, such as

Moscow, Russia
in August 2010

The major forms of pollution are listed below along with the particular

relevant to each of them:


Natural causes

Air pollution produced by ships may alter clouds, affecting global temperatures.

One of the most significant natural sources of pollution are volcanoes, which during eruptions release large quantities of harmful gases into the atmosphere. Volcanic gases include carbon dioxide, which can be fatal in large concentrations and contributes to climate change, hydrogen halides which can cause acid rain, sulfur dioxides, which are harmful to animals and damage the ozone layer, and hydrogen sulfides, which are capable of killing humans at concentrations of less than 1 part per thousand.[19] Volcanic emissions also include fine and ultrafine particles which may contain toxic chemicals and substances such as arsenic, lead, and mercury.[20]

suffocation. Large quantities of fine particulates are found within wildfire smoke as well, which pose a health risk to animals.[21]

Human generation

livestock farms (dairy cows, pigs, poultry, etc.), PVC factories, metals production factories, plastics factories, and other heavy industry. Agricultural air pollution comes from contemporary practices which include clear felling and burning of natural vegetation as well as spraying of pesticides and herbicides.[27]

About 400 million metric tons of

China overtook the United States as the world's biggest producer of CO2,[33] while still far behind based on per capita pollution (ranked 78th among the world's nations).[34]

An industrial area, with a power plant, south of Yangzhou's downtown, China

Chlorinated hydrocarbons (CFH), heavy metals (such as chromium, cadmium – found in rechargeable batteries, and lead – found in lead paint, aviation fuel, and even in certain countries, gasoline), MTBE, zinc, arsenic, and benzene are some of the most frequent soil contaminants. A series of press reports published in 2001, culminating in the publication of the book Fateful Harvest, revealed a widespread practise of recycling industrial leftovers into fertilizer, resulting in metal poisoning of the soil.[35] Ordinary municipal landfills are the source of many chemical substances entering the soil environment (and often groundwater), emanating from the wide variety of refuse accepted, especially substances illegally discarded there, or from pre-1970 landfills that may have been subject to little control in the U.S. or EU. There have also been some unusual releases of polychlorinated dibenzodioxins, commonly called dioxins for simplicity, such as TCDD.[36]

Pollution can also occur as a result of natural disasters. Hurricanes, for example, frequently result in sewage contamination and petrochemical spills from burst boats or automobiles. When coastal oil rigs or refineries are involved, larger-scale and environmental damage is not unusual. When accidents occur, some pollution sources, such as nuclear power stations or oil ships, can create extensive and potentially catastrophic emissions.[37]

The motor vehicle is the most common cause of noise pollution, accounting for over 90% of all undesirable noise globally.

Plastic pollution it’s choking our oceans by making plastic gyres, entangling marine animals, poisoning our food and water supply, and ultimately inflicting havoc on the health and well-being of humans and wildlife globally. With the exception of a small amount that has been incinerating, virtually every piece of plastic that was ever made in the past still exists in one form or another.  And since most of the plastics don’t biodegrade in any meaningful sense, all that

plastic waste could exist for hundreds or even thousands of years. If plastic production isn’t circumscribed, plastic pollution will be disastrous and will eventually outweigh fish in oceans.[38]

Greenhouse gas emissions

Historical and projected CO2 emissions by country (as of 2005).
Source: Energy Information Administration.[39][40]

Carbon dioxide, while vital for photosynthesis, is sometimes referred to as pollution, because raised levels of the gas in the atmosphere are affecting the Earth's climate. Disruption of the environment can also highlight the connection between areas of pollution that would normally be classified separately, such as those of water and air. Recent studies have investigated the potential for long-term rising levels of atmospheric carbon dioxide to cause slight but critical increases in the acidity of ocean waters, and the possible effects of this on marine ecosystems.

In February 2007, a report by the Intergovernmental Panel on Climate Change (IPCC), representing the work of 2,500 scientists, economists, and policymakers from more than 120 countries, confirmed that humans have been the primary cause of global warming since 1950. Humans have ways to cut greenhouse gas emissions and avoid the consequences of global warming, a major climate report concluded. But to change the climate, the transition from fossil fuels like coal and oil needs to occur within decades, according to the final report this year from the UN's Intergovernmental Panel on Climate Change (IPCC).[41]


Human health

Overview of main health effects on humans from some common types of pollution[42][43][44]

Pollution effects humans in every part of the world. An October 2017 study by the Lancet Commission on Pollution and Health found that global pollution, specifically toxic air, water, soils and workplaces, kills nine million people annually, which is triple the number of deaths caused by AIDS, tuberculosis and malaria combined, and 15 times higher than deaths caused by wars and other forms of human violence.[45] The study concluded that "pollution is one of the great existential challenges of the Anthropocene era. Pollution endangers the stability of the Earth’s support systems and threatens the continuing survival of human societies."[3]


WHO estimated in 2007 that air pollution causes half a million deaths per year in India.[48] Studies have estimated that the number of people killed annually in the United States could be over 50,000.[49] A study published in 2022 in GeoHealth concluded that energy-related fossil fuel emissions in the United States cause 46,900–59,400 premature deaths each year and PM2.5-related illness and death costs the nation $537–$678 billion annually.[50]

developing countries. For example, an estimated 500 million Indians have no access to a proper toilet,[51][52] Over ten million people in India fell ill with waterborne illnesses in 2013, and 1,535 people died, most of them children.[53] As of 2007, nearly 500 million Chinese lack access to safe drinking water.[54]

Acute exposure to certain pollutants can have short and long term effects. Oil spills can cause


Socio economic impacts

The health impacts of pollution have both direct and lasting social consequences. A 2021 study found that exposure to pollution causes an increase in violent crime.[55] A 2019 paper linked pollution to adverse school outcomes for children.[56]A number of studies show that pollution has an adverse effect on the productivity of both indoor and outdoor workers.[57][58][59][60]


Pollution has been found to be present widely in the

environment.A 2022 study published in Environmental Science & Technology found that levels of anthropogenic chemical pollution have exceeded planetary boundaries and now threaten entire ecosystems around the world.[6][7]

There are a number of effects of this: