Pollution is the introduction or presence of contaminants that can have a damaging effect on the natural environment. The two most prominent forms of pollution are air and water pollution, though many other forms exist. For example: sound, light, and soil pollution.
Many forms of pollution can have a broad and long-lasting negative impact upon the health of humans, plants and animals, or entire ecosystems.
Air pollution and its impact
Air pollution is primarily introduced through the burning of fossil fuels. The largest contributors are fossil-fuel-powered vehicles (cars, trucks, aircraft, ships, etc.) and coal- or oil-burning power plants and factories. However, any activity that involves the burning of wood or fossil fuels can release particulate matter. This includes household-level sources such as tobacco products, stoves and ovens, candles, and fireplaces. Volcanos and wildfires can also be notable sources of air pollution.
Air pollution has been proven to contribute to health problems including breathing issues, worsening of asthma, and even congenital disabilities. According to Pure Earth, toxic pollution is among the leading risk factors for non-communicable diseases globally. Non-communicable diseases account for 72% of all deaths, 16% of which are caused by toxic pollution. Toxic pollution is responsible for 22% of all cardiovascular disease, 25% of stroke deaths, 40% of lung cancer deaths, and 53% of deaths from chronic obstructive pulmonary disease.
This aligns with data from the World Health Organization (WHO), which indicates that air pollution causes 7 million premature deaths every year. 91-99% of the world's population lives in places where air quality exceeds WHO recommended guidelines.
The United States Environmental Protection Agency measures five major pollutants, all of which are regulated via the Clean Air Act:
- ground-level ozone
- particle pollution (also known as particulate matter, including PM2.5 and PM10)
- carbon monoxide
- sulfur dioxide
- nitrogen dioxide
Of these, particle pollution is the most commonly monitored. The World Health Organization evaluated the concentration of PM2.5 particles to determine the most polluted place on Earth. PM2.5 (fine particulate matter 2.5) refers to tiny particles or droplets in the air that are 2.5 microns (µg) or less in diameter.
PM2.5 is an air pollutant and can be a health concern when present in high concentrations. Cities such as New York, issue a PM2.5 Health Advisory when conditions are considered to be unhealthy for sensitive groups. In recent years, wildfires have triggered an increasing number of PM2.5 warnings in many other regions as well, including portions of Europe, Australia, Africa, and the western United States.
The World Health Organization (WHO) target for air pollution is 0-10 µg/m³. IQ Air, which measures pollution in 109 countries around the globe, considers measurements above 35.5 to be unhealthy for sensitive groups, levels between 55.5 and 150.4 to be unhealthy for all, and anything higher is either very unhealthy (150.5-250.4) or hazardous (250.5 or higher).
Top 10 Countries with the Worst Air Pollution - PM2.5 exposure (µg/m³) - IQ Air 2020
- Bangladesh - 77.10
- Pakistan - 59.00
- India - 51.90
- Mongolia - 46.60
- Afghanistan - 46.50
- Oman - 44.40
- Qatar - 44.30
- Kyrgyzstan - 43.50
- Indonesia - 40.70
- Bonsia & Hezegovina - 40.60
While the IQ Air list is respectable, it is not the only available source of air pollution data. Using data from Seattle, Washington's Institute for Health Metrics and Evaluation, the Health Effects Institute has released its own list ranking the levels of air pollution of 196 nations via the State of Global Air report.
Top 10 Countries with the Worst Air Pollution - PM2.5 exposure (µg/m³) - State of Global Air 2020 (2019 data)
- India - 83.2
- Nepal - 83.1
- Niger - 80.1
- Qatar - 76
- Nigeria - 70.4
- Egypt - 67.9
- Mauritania - 66.8
- Cameroon - 64.5
- Bangladesh - 63.4
- Pakistan - 62.6
The two lists differ significantly, most likely due to differences in recording systems and the fact that the IHME data includes 196 countries to IQ Air's 109. Still, many of the same countries appear, with the rankings often decided by thin margins.
The Air Quality Index (AQI) used by the United States Environmental Protection Agency is slightly more lenient than the IQ Air scale (by about 50 µg/m³). Values of 0-100 are generally thought of as satisfactory. However, values from 101-200 are considered unhealthy for certain at-risk groups, values 201-300 are viewed as unhealthy for everyone, and levels above 300 are deemed hazardous for all.
The cleanest countries in the world, as determined by the Environmental Performance Index (EPI), have high air quality, clean water, and strong environmentally-friendly policies and initiatives. These countries include Switzerland, France, and Denmark.
As the damage from pollution has become more apparent, more countries are looking to green alternatives to prevent further damage to the Earth. Solar and wind energy, eco-friendly building materials, and non-toxic products are increasingly being used to preserve the planet. While these green initiatives are taking place around the world, some countries have a long way to go.
Country-by-country profiles of the nations with the worst air pollution in the world (per IQ Air 2020)
Bangladesh is the most polluted country in the world, with an average PM2.5 concentration of 77.10, which is nonetheless a decrease from 83.30 in 2019 and 97.10 in 2018. The country's primary environmental pollutants are air and water pollution, groundwater contamination, noise pollution, and solid wastes. Dhaka City is one of the most polluted cities in the world. In terms of air pollution, Bangladesh's largest source is its brickmaking industry, which employs one million people and creates 23 billion bricks every year. The kilns used in brickmaking burn wood or coal and create mass amounts of smoke and dust. Due to increased demand for bricks, the brickmaking industry is only expected to grow more, leading to more air pollution.
The second-most polluted country in the world is Pakistan, which has an average PM2.5 concentration of 59.00. AQI levels in Punjab were consistently between the "near unhealthy" or "very unhealthy" ratings for most of 2019 and even reached as high as 484. Pakistan is experiencing rising pollution from the growing number of vehicles on the roads, large-scale losses of trees, smoke from bricks kiln and steel mills, and the burning of garbage. The Pakistan minister for climate change blamed India for Pakistan's smog; however, Pakistani citizens blame their government for simply not doing enough to monitor or combat the crisis.
India the third-most polluted country in the world, with an average PM2.5 concentration of 51.90. Of the 30 most polluted cities in the world, 21 of them are located in India. The most polluted city in India and the world is Kanpur, where the city's medical college receives about 600 respiratory illness patients per month. India's unhealthy pollution levels are from sources such as vehicles, the burning of coal and wood, dust storms, and forest fires. Delhi, India's capital region, is notorious for some of the worst air in India, forcing flight cancellations, causing traffic accidents, closing of schools, and even turning the white marble walls of the Taj Mahal yellow and green. Rural areas are also heavily affected by pollution in India, as people rely on fuels such as wood and dung for cooking and heating and still practice the burning of crop stubble.
Mongolia is the fourth-most polluted country in the world. Mongolia's average PM2.5 concentration is 46.60. The largest pollution source in Mongolia is the burning of coal and other biomass, such as wood or crop residue, in stoves. In Mongolia's capital, Ulan Bator, respiratory infections have increased 270% over the last ten years, and children that live in the capital city have a 40% lower lung function than those living in rural areas. About 70-90% of pregnant mothers being treated at a family health center in Mongolia are negatively impacted by air pollution. Infants as young as two days old are being diagnosed with pneumonia or other respiratory illnesses.
Afghanistan is the fifth-most polluted country in the world, with an average PM2.5 level of 46.50. In 2017, numbers show that air pollution was more dangerous than the war in Afghanistan. That year, about 26,000 people lost their lives due to air pollution-related diseases while 3,483 people lost their lives due to conflict. About 80% of drinking water in Afghanistan is polluted as well due to low rainfall, irregular use of groundwater, and insufficient infrastructure in cities. The lack of clean drinking water commonly results in food poisoning.