1. Milan, Italy
Ah, Milan, home to great shoes, high fashion and more pm10ssmall pollution particles that can cause cancer and breathing problemsthan any other city in Europe. In fact, according to a study by Italian environmental group Legambiente, Milan has more smog than any other city in Europe and the continents second-highest level of ozone. Most of the problem comes from the citys love of driving, but thats changing quickly: Congestion pricing in downtown Milan implemented in January has dropped traffic by 26 percent and, residents hope, will lead to drops in smog as well.
2. Norilsk, Russia
According to a study of the worlds most polluted places by environmental think tank the Blacksmith Institute, Norilsk, Russiahome to 134,000 residents and the worlds largest heavy-metal-smelting firm, Norilsk Nickelmakes the top 10. Norilsks Soviet-era plant spews tons of heavy metals like nickel and cobalt into the air, leading to severe respiratory and throat diseases in children and a life expectancy 10 years below the Russian average for plant workers. But the company says its taking measures to clean things up, investing in technology to sequester heavy-metal dust, and says it plans to move the smelter outside the city limits in the near future.
3. Pittsburgh, Pennsylvania
Pittsburgh recently wrested the title of Americas most polluted city from Los Angelesat least when it comes to short-term particle pollution like soot, aerosols, heavy metals and exhaust. But the city of 335,000, which has transitioned from an industrial town to one of the countrys most livable cities, may not be to blame for its bad air. According to some research, much of Pittsburghs pollution is blown in from factories and power plants in Ohio.
4. Mexico City, Mexico
Mexico City is a natural pollution trap. Surrounded by mountains on three sides and located 7,400 feet above sea level, the soot and exhaust from the citys four million mostly high-polluting cars gets trapped in a cloud over the city, which experiences 300 days a year of exceedingly high ozone levels. To fix things, the city has begun a pilot project retrofitting 25 diesel buses with particulate filters. Now, if it could only retrofit the other 2,975 buses .
5. Dakar, Senegal
Dakar is West Africas cosmopolitan hub, but just a stones throw from the city is an environmental catastrophe. The Baie de Hanne, which provides drinking and household water to two million people, contains levels of fecal streptococci more than 17 times World Health Organization standards, as well as a stew of heavy metals and tannery waste. The Blacksmith Institute is currently working with the World Bank to implement an international cleanup effort.
6. Sumgayit, Azerbaijan
Sumgayit used to be the New Jersey of the Soviet Unionthe town was the nations center of chemical and pesticide production. Today, it is still feeling the aftereffects of years of untreated, mercury-contaminated waste dumped directly into streams feeding the Caspian Sea. Cancer rates in the city of 275,000 are sky-high. The World Bank has stepped into the city, which was declared an environmental disaster area, and is helping to clean up old plant sites.
7. Linfen, China
This city of more than four million is in the heart of Shanxi, Chinas coal-production hub, and has frequently been deemed the most polluted city in the world; citizens suffer from choking clouds of coal dust as well as drinking water polluted with arsenic. But Linfen is not the only city in the country with environmental woesthe World Bank estimates that 16 of the worlds 20 most polluted cities are found in Chinas industrial areas
8. La Oroya, Peru
For 85 years, the citizens of La Oroya have been smelting lead, copper and zinc. Now 99 percent of the towns children harbor levels of toxic lead that exceed acceptable limits. Acid rain has destroyed most of the surrounding vegetation, turning the region into a wasteland. So far, the Peruvian government has put the city of 35,000 on a list for environmental remediation, but activists are attempting to pressure the smelters owner, the Doe Run company of Missouri, to step in and begin a serious cleanup.
9. Cubatao Valley, Brazil
The Cubatao Valley, a region home to more than two million people, is Brazils industrial and chemical heart. The Cubatao River, the areas main water source, is clogged with 1.5 million tons of raw sewage per year and more than 10,000 kilograms of toxic industrial waste per month. A study in 1980 showed that over a third of residents had tuberculosis, pneumonia, emphysema and other respiratory diseases. Since 2000, Brazils new water agency has made a concerted effort to clean up the Cubatao region, investing some $1.1 billion to improve the Tiete River, another major waterway in the valley.
10. Kabwe, Zambia
For 92 years, the lead and copper mines outside Kabwe, Zambia, ran with little or no environmental protections. Its been more than a decade since the smelters shut down, and the lead level found in the average child, who bathes in a lead-contaminated stream and is constantly exposed to contaminated soil, is still five to 10 times the maximum allowed by the U.S. EPA. In many cases, children carry almost fatal levels of contamination. So far, the World Bank has provided $40 million to help relocate some neighborhoods in Kabwe, and several other international and local groups are implementing extensive programs to teach residents about lead poisoning.
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xMustiiej70"
The World's Dirtiest Cities | Popular Science
anyway guys most of the cities in India need some hell of an effort to make cleaner..I was surprise to see only 2 cities from my country was in that 25 lists..so i can guess what other cities look like 
