Sept 12 (Reuters) - Russia and two former Soviet republics have four of the world's top 10 most polluted places, according to the Blacksmith Institute, a New York-based nonprofit group.

Blacksmith did not rank the top 10 because complete health records from some developing countries were unavailable. For each site the group included the number of potentially affected people, who could face problems ranging from asthma to premature death.

The annual list was compiled with help from specialists at Harvard University, Johns Hopkins University, Hunter College in New York, India's ITT, University of Idaho, Mt. Sinai Hospital in New York and others. The full report can be found at www.worstpolluted.com.

Below are the worst polluted places listed alphabetically.

Sumgayit, Azerbaijan

- Potentially affected people: 275,000

- Pollutants: Heavy metals, organic chemicals

- Sources: Petrochemical and industrial complexes

Linfen, China

- Potentially affected people: 3,000,000

- Pollutants: Fly-ash, volatile organic compounds, lead

- Sources: Car and industrial emissions from coal industry

Tianying, China

- Potentially affected people: 140,000

- Pollutants: Lead and heavy metals

- Sources: Mining and processing

Sukinda, India

- Potentially affected people: 2,600,000

- Pollutants: Hexavalent chromium

- Sources: Chromite mines

Vapi, India

- Potentially affected people: 71,000

- Pollutants: Chemicals and heavy metals

- Sources: Industrial estates

La Oroya, Peru

- Potentially affected people: 35,000

- Pollutants: Lead, copper, zinc

- Sources: Heavy metal mining

Dzerzhinsk, Russia

- Potentially affected people: 300,000

- Pollutants: Sarin, lead, phenols

- Sources: Cold War-era chemical weapons, manufacturing

Norilsk, Russia

- Potentially Affected People: 134,000

- Pollutants: Heavy metals, phenols

- Sources: Nickel mining

Chernobyl, Ukraine

- Potentially affected people: 5.5 million

- Pollutants: Radioactive dust including uranium, other metals

- Sources: Nuclear meltdown of reactor core in 1986

Kabwe, Zambia

- Potentially affected people: 255,000

- Pollutants: Lead, cadmium

- Sources: Lead mining and processing