Sumqayit in Azerbaijan gained the dubious distinction this week of being added to Blacksmith Institute's top 10 list of the world's most polluted sites. Yet another heir to the toxic legacy of Soviet industry, the city of 275,000 souls bears heavy metal, oil and chemical contamination from its days as a center of chemical production. As a result, local Azeris suffer cancer rates 22 to 51 percent higher than their countrymen and their children suffer from a host of genetic defects ranging from mental retardation to bone diseases.

"As much as 120,000 tons of harmful emissions were released on an annual basis, including mercury," says Richard Fuller, founder of Blacksmith, an environmental health organization based in New York City. "There are huge untreated dumps of industrial sludge."

Fuller says the list includes "places that are highly polluted in the developing world, where children are dying in droves or living with chronic disease… areas of desolation and disgust at what man has wrought." Joining Sumqayit as the worst polluted:

Chernobyl, Ukraine — The fallout from the world's worst nuclear power accident continues to accumulate, affecting as many as 5.5 million people and leading to a sharp rise in thyroid cancer. The incident has also blighted the economic prospects of surrounding areas and nations. "Belarus is very agricultural," says Stephan Robinson, a director at Green Cross Switzerland, an environmental group that collaborated on the report. "Through Chernobyl, they lost access to world markets for their produce."

Dzerzinsk, Russia — A center of Cold War chemical manufacturing, the city's 300,000 residents have one of the lowest life expectancies in the world thanks to waste injected directly into the ground. "Average life expectancy is roughly 45 years," Robinson says. "Fifteen to 20 years less than the Russian average and about half a Westerner's."

Kabwe, Zambia — The second largest city in this southern African country was home to one of the world's largest lead smelters until 1987. As a result, the entire city is contaminated with the heavy metal, which can cause brain and nerve damage in children and fetuses. "Measurements of children's blood levels of lead average over 50 micrograms per deciliter and some were over 100," Fuller says. "For every 10 points above 10 micrograms per deciliter [(the U.S. Centers for Disease Control standard for treatment)] that your blood level goes up, your IQ drops."

La Oroya, Peru — Although this is one of the smallest communities on the list (population 35,000) it is also one of the most heavily polluted due to lead, copper and zinc mining by U.S.-based Doe Run mining company.

Linfen, China — a city in the heart of China's coal region in Shanxi Province, its three million inhabitants choke on dust and drink arsenic that leaches from the fossil fuel. In addition, "it is difficult to see," Robinson says, "the air is heavily polluted."

Norilsk, Russia — This city above the Arctic Circle contains the world's largest metal smelting complex and, therefore, some of the world's worst smog. "There is so much pollution going into the air from this place that there is no living piece of grass or shrub within 30 kilometers of the city," Fuller says. "Contamination [with heavy metals] has been found as much as 60 kilometers away."

Sukinda, India — Home to one of the world's largest chromite mines—used to make steel stainless, among other things—and 2.6 million people, the waters of this valley contain carcinogenic hexavalent chromium compounds courtesy of 30 million tons of waste rock lining the Brahmani River. "Hexavalent chromium is very toxic and very mobile," notes David Hanrahan, Blacksmith's London-based director of global programs.

Tianying, China — The center of Chinese lead production, this town of 160,000 qualifies as one of the eight most polluted areas in the country, according to the Chinese government. Lead concentrations in the air and soil are 8.5 to 10 times above national health standards and lead dusts local crops at levels 24 times higher than such health standards.

Vapi, India — This town at the end of India's industrial belt in the state of Gujarat houses the dumped remnant waste of more than 1,000 manufacturers, including petrochemicals, pesticides, pharmaceuticals and other chemicals. "The companies treat wastewater and get most of the muck out," Hanrahan says. "But there's nowhere to put the muck, so it ends up getting dumped."

Blacksmith Institute compiled the list, which extends to 20 more sites in the "Dirty 30," by comparing the toxicity of the contamination, the likelihood of it getting into humans and the number of people affected. Places were bumped up in rank if children were impacted. No U.S. or European sites made the list thanks to a mop-up of lingering human health hazards over the past several decades, but that does not mean the developed world is not a contributor. "The nickel we use in our cars or elsewhere is likely to have come from Norilsk," Fuller notes. "And some of the lead in our car batteries will have come from one of these places."

Despite the massive pollution, it would be relatively easy and cheap to clean up the most dangerous hazards at these contaminated sites, Fuller argues. Economic development has already led to construction of cleaner new plants in some places and small efforts and investments can net major gains, he says.

For example, it costs just $15,000 to save an estimated 350 lives by simply digging up radioactive contaminated soil from the Mayak plutonium facility that had been deposited on the shore of the Techa River in the Russian town of Muslyomova. Similar cost-effective efforts are underway across the globe. "For about $200, the cost of a refrigerator, we are able to save someone's life," Fuller says, citing a recent Blacksmith analysis conducted with the help of Mount Sinai School of Medicine and Hunter College in New York City as well as Johns Hopkins University in Baltimore. "Small amounts of money have gone an awfully long way to cleaning some of these up."

But there are also many sites this survey likely overlooks; Fuller conservatively estimates that, at worst, they have captured only one third of the world's most polluted areas because of spotty coverage in central Asia and Central and South America. After all, Sumqayit made the list this year for the first time. "We were quite surprised," he admits, "to have new additions to the list that we'd never heard of."