Which cities in the world are the most polluted? That depends on who you ask, and what exactly you are looking for. Some of the data is from the 2016 WHO (World Health Organization) report. Air quality data from 3,000 cities worldwide was used to create a list of urban areas most affected by air pollution. But air pollution is only one part of the puzzle when it comes to environmental contamination.
It's true that the list includes a hugely disproportionate number of cities in what we'd call developing countries. That's just because, while we've had a century or more to pollute the landscape in places like North America and Western Europe, other regions of the world have to go through all that industrial development in double-time. Throw in a lot of money to be made in growing economies, and it's a recipe for the kind of pollution overkill some places experience. As the WHO report notes, those cities should be recognized for taking the first step in recognizing the problem by making their air quality measurements public.
Here's a look at some of the most polluted cities in the world, and some of the reasons why. And, while you may consider yourself lucky if you happen to be halfway across the world from any of these locales, remember that the wind and the water don't know about national boundaries, and that contamination spreads. It's not like the issues aren't known. Officials in China and many other countries have implemented measures and programs to help curb the pollution problem. The question is, do we have enough time to wait until everyone, everywhere decides to act?
15 Linfen, China
Coal is king in Linfen, China, and it's unfortunate for the people who have to breathe the city's soot-filled air every day. Linfen is often called the most polluted city in the world. At one time, Linfen was known as "the fruit and flower town," a small farming community in the Shangxi Province known for its natural springs. Nowadays, a blanket of yellowy gray smog covers the city on a daily basis, and its residents have forgotten what a sunset looks like without that surreal, apocalyptic glow. As if the plethora of legal coal mines wasn't enough, the area is plagued by illegal coal mines that operate without any oversight or attention to regulations. The coal burns, and as the city is located in a basin-like area, the smog gathers over the city without being able to disperse. Overall, China produces nearly half the world's supply of coal. Most importantly, coal produces about 90 percent of China's electricity, and fuels the giant Chinese manufacturing sector -- including the factories that made your PC and iPhone.
14 Onitsha, Nigeria
Pollution is measured in various ways. One standard for measuring air pollution is to look at the level of particulate matter – that means the tiny particles that make up the dust and smog in the air. PM10 refers to particulate that measures between 2.5 and 10 micrometers in diameter. At that size, you can see them in the air as smog, but they are small enough to be inhaled directly into the lungs. Onitsha, Nigeria, holds the dubious distinction of having the highest concentration of PM10 in the air in the world at a whopping 594 micrograms per cubic meter, the measurement used by WHO. The WHO's guidelines call for less than 20 micrograms per cubic meter. Where does it come from? The population of Onitsha has swelled rapidly, doubling in a few short years. There are a number of significant sources of particulate matter in the air, including burning garbage, open cooking fires, vehicle emissions from poor quality diesel fuel, and industry, including many metal working shops. Along with the air, there are high levels of arsenic, mercury, lead, copper, and iron in the water. There is very little public awareness of the issue, to compound the problem, and consequently very little effort on the part of government or other authorities to do anything about it.
13 Peshawar, Pakistan
Peshawar, Pakistan ranks second in the WHO list of cities with the most polluted air. The listing specifically looks at the amount of particulate matter in the air. Peshawar's results are particularly troubling in that they involve a high concentration of PM2.5, measuring between 40 and 90 in all areas of the city, well above the guidelines of just 15 micrograms per cubic meter. Microscopic PM2.5 represents airborne matter that is so small, it can not only be inhaled into the lungs, it can pass right into the bloodstream. Scary stuff. The concentration of PM2.5 has a direct impact on human health. According to the EPA, regular exposure at the levels recorded in Peshawar over a decade or more, is linked to an increased risk of death. As with many urban areas, the challenge is that there are multiple sources of those particles that make up smog, including garbage burning, smoke from brick kilns, vehicle emissions, construction work, and more.
12 Zabol, Iran
It's a strange thing, but according to the data collected so far, there's a link between wealth and the type of particulate matter found. Poorer countries tend to have higher concentrations of PM10 -- possibly from more open fires, such as cooking fires -- while as countries get wealthier, the problem shifts to deadly PM2.5. In the case of Zabol, a city in the eastern part of Iran near Afghanistan, Mother Nature plays a key role. Civilization dates back more than 5,000 years in Zabol; nowadays it's a city with a lot of social problems like poverty, and the highest recordings of PM2.5 in the world, reaching 217 micrograms per cubic meter. In Zabol, the summer is known as "120 days of wind", when temperatures climb above 105 degrees Fahrenheit. Dust storms rage constantly – about 80 every year – and about 15 years ago, a nearby wetland dried up, making the situation worse. Schools and government offices are closed when conditions become severe, and there is a high rate of lung disease from the unusual level of dust pollution. Disappearing wetlands and shortsighted water management are making the dust storms worse every year.
11 Riyadh, Saudi
A combination of man made and natural forces puts Riyadh, Saudi Arabia, on the WHO list of most polluted cities. The city measured PM10 levels averaging at 368, and PM2.5 levels at 156. Riyadh, the capital of the Kingdom of Saudi Arabia, is in the midst of a huge growth spurt, and the alarming rise in pollution is one of the symptoms. Heavy vehicular traffic and poor quality fuels, along with industry emissions, account for a great deal of the airborne particles that turn the skies over the city a sickly cross between yellow and gray. A cement factory and fuel refineries have been blamed. Sandstorms whipping across the desert add dust and sand to the mix, and create a situation that's taking its toll on the city's residents.
10 Citarum River, Indonesia
The Citarum river runs from the Wayang Mountain to the Java Sea, not far from Jakarta, Indonesia. More than 30 million people rely on its waters for uses from their daily shower to industry and agriculture, especially the 5 million who live in the river basin. Rapid industrialization and lack of regulation has created a monster, now considered among the most polluted rivers in the world and possibly even holding the number 1 spot. There are more than 200 textile factories along the river banks, spewing dyes and chemicals that include arsenic, lead, and mercury, into the water. The dyes discolor the water, which takes on a sharp smell. There's so much plastic and garbage floating on the water that you can barely see the surface. Untreated sewage release is another huge problem that plagues all of Indonesia's fresh water supply, including the Citarum river. Dead fish litter the water and resourceful fishermen have turned to collecting plastic garbage to deliver to recycling depots instead.
9 Riachuelo Basin, Argentina
The Matanza-Riachuelo river basin in Argentina runs through 14 municipalities in Buenos Aires, the nation's capital. Before it does so, about 15,000 industries, including chemical manufacturing plants, release runoff directly into the water, leading to levels of toxic metals like zinc, copper, nickel, lead, and chromium in the soil along its banks, never mind what is actually in the water itself. About 90,000 tons of heavy metals and other waste is dumped into the river on a yearly basis. About 20,000 people actually live along its banks, and most of them live on land that has been found uninhabitable by human beings. Another 8 million people live in the river basin area. Among the many health problems the environmental degradation has caused are elevated levels of intestinal and respiratory diseases, and cancer. The water is not considered safe to drink, yet residents in the most affected area have few other options. Clean ups have been touted and planned by the government for years, but with few tangible results so far.
8 Dzerzhinsk, Russia
The Guinness Book of World Records named Dzerzhinsk, Russia as the most chemically polluted city in the world in 2007. The city was the main site for chemical manufacturing during the Soviet era, and that included chemical weapons. It is now estimated that about 300,000 tons of chemical waste was dumped in and around the city between 1930 and 1998. Water samples around the city show concentrations of dioxin thousands of times above accepted guidelines. Along with the city itself, the nearby lake surrounded by barbed wire fence and known as "the Black Hole" is called the world's most contaminated. The waters are chock full of phenol, a corrosive substance that can cause third-degree burns if you touch it and was used by the Nazis to execute prisoners by injection. The results of decades long contamination are grim. Cancers and other disorders of the eye, lungs, and kidneys are rampant. Life expectancy in the city of about 245,000 people runs to about 47 for women and 42 for men, and the death rate out strips the birth rate by more than two and a half times.
7 Mailuu-Suu, Kyrgyzstan
Once upon a time, when Soviet Russia was a thing, the town of Mailuu-Suu in Kyrgyzstan was completely closed to the outside. In the town, select workers got premium pay grades for extremely dangerous work processing uranium. More than 10,000 tons of radioactive uranium was produced here to power Soviet atomic energy plants between 1946 and 1967. Unfortunately, that waste -- in 23 tailing dumps and 13 waste rock dumps throughout the area -- still exists. Radiation and radon gas, produced by decaying uranium, and known to cause lung cancer, are the main risks. There are stories of rampant cases of cancer and leukemia, but residents say the government does little to help the area, and clean-up efforts have been limited to say the least. Since the collapse of the Soviet Union in 1991, there has been little maintenance. The protective dams around the tailing ponds are in bad shape, and the radioactive material often leaches into the nearby river. Seismic activity makes the issue even more urgent. In 2005, an earthquake sent over 1,000,000 cubic feet of material into the river.
6 Tianying, China
About half of China's lead production was once located in Tianying, and the heavy metal has found its way into the lives and fabric of its residents. In fact, the state run lead foundry sits right in the center of town. The concentration of lead in the air and soil have been measured at up to 10 times the national guidelines. Lead dust coats crops in the area at levels almost 25 time higher than recommended levels. Lead collects in the body over time and is particularly worrying when it comes to children, where prolonged exposure can stunt brain development and even result in lower IQs. Lead, we'll point out, is largely used in the modern world in car batteries and weights, among other things. Things are said to have improved over the last decades as the use of lead in many things like household paints and plumbing has been banned, but an area within about a mile radius of the city's main plant remains uninhabitable.
5 Sukinda, India
Chromium is used to make shiny stainless steel and tanning leather, among other things, and one of the world's largest chromite mines is located in Sukinda, India. The city is home to about 2.6 million people, and 30 million tons of waste rock that lines the Brahman River. Hexavalent chromium, a processed form of chromium ore, is highly toxic. About 60 percent of the water in Sukinda contains more than double the international guidelines for hexavalent chromium, and one health organization estimated that about 85 percent of all deaths in the area of the mines can be attributed to chromite exposure. The problem is that there are few, if any, regulations governing the mining and processing. Untreated water from the mines runs directly into the river, and the area is also prone to floods, meaning the toxic effect is being spread even more widely. Chromite exposure causes stomach bleeding, tuberculosis and asthma, along with infertility and birth defects.
4 Kabwe, Zambia
Kabwe, Zambia, was founded after zinc and lead were discovered there in 1902, and its legacy as a mining town is slowly killing its residents. Lead is the major problem in Kabwe, Zambia, a city that was once home to one of the world's largest lead smelters. The smelter closed up shop in 1987, but the damage was already done, with lead contamination all over the city. Blood samples taken from residents have shown levels of lead at 60 percent above the lethal level. Lack of any kind of regulation meant sloppy waste disposal, and because of it, the city's soil and water are contaminated. A clean-up effort in recent years has helped somewhat, but the problem persists, in part because a number of smaller lead smelters emerged after the big plant closed. Along with lead dust, soil samples within a 15 mile radius of the town have found heavy concentrations of cadmium, copper, and zinc.
3 La Oroya, Peru
Doe Run mining company is headquartered in the U.S., but its most notorious operation is in La Oroya, Peru. The smelter it ran in the Andean city from 1922 to 2009 has left La Oroya with a legacy of lead poisoning and metal contamination. Ninety-nine percent of the city's children have blood lead levels up to triple the recommended limits. Sulfur dioxide, arsenic, and cadmium have also been measured at unacceptable levels in the soil. The American company abandoned the plant in 2009, partly because of the cost of pollution clean-up. Peru's current president, Pedro Pablo Kuczynski, has vowed to reopen the polymetallic smelter, now almost a century old, along with one of the area's copper mines, with an auction slated for March 2017. So far, his efforts have been hampered by the prospect of having to deal with the existing pollution problem and the remediation required, along with needed upgrades to the smelter itself.
2 Norilsk, Russia
With all due respect, we'd have to say that living in Norilsk, Russia doesn't sound like a lot of laughs. It's not only often called the most polluted city in Russia, it's also been dubbed the coldest city on earth. The average temperature for the small city that lies above the Arctic Circle is a mere 14 degrees Fahrenheit, and on a chilly winter day, it can drop to a bone-chilling minus 67. That's minus 67. During a bad winter, children sometimes have to stay indoors for months at a time. It's completely dark for two months of the year, with snowstorms taking up about 130 days a year. In September 2016, the city made international headlines after the waters of the Daldykan river went a bright red color. After some hemming and hawing, Norilsk Nickel company admitted a spillover from one of its operations. That's just business as usual in this contaminated city. The nickel plant just closed down in 2016, once emitted more than 385,000 tons of sulfur dioxide into the air, known to cause a number of respiratory conditions and diseases. While the largest plant has closed, there are still many smaller operations that have taken up the slack. Nickel isn't the only metal in town, either. The city is a significant producer of palladium, platinum, and copper -- metals that turn up in everything from your cellphone to kitchen appliances – in what is billed as the world's largest metal smelter.
1 Chernobyl, Ukraine
The Ukrainian city of Chernobyl makes the list more than three decades after the nuclear plant meltdown that caused fear around the world in 1986 – and it'll be on this list for tens of thousands of years to come. That's how long it will take for the air, water, and soil to be remediated from the contamination it suffered during the infamous incident. The so-called exclusion zone covers a 19-mile radius around the ruined nuclear power plant. The consequences are real and ongoing. Between 1992 and 2002, there were over 4,000 cases of thyroid cancer among children who had living in the area. It is suspected that leaks are leading to contaminated groundwater. But, it could have been much worse. Although a great deal of radiation was released at the time -- more than 100 times the amount produced by the atomic bombs dropped on Nagasaki and Hiroshima -- most of the current radioactivity is contained within the sarcophagus that was created around the nuclear core. However, the lifespan of that concrete shell is nearing its end, and replacement programs are being developed.
Sources: The Guardian; The Tribune; The Telegraph.