SCIENCE / ENVIRONMENT

List: Top Ten Most Polluted Cities in the World

Date: September 2007

Source: Blacksmith Institute

Base: 400 cities nominated as pollution blackspots.

Notes: The list is not in rank order. The full methodology, plus a list of a 'Dirty Thirty' cities selected by the Institute, is available at the link above (pdf form). The scoring system involves an algorithm based on a selection criteria of hazard assessment that is summarised as: Impact = Pollutant x Pathway x People. The main factors are: Severity of Toxin, Scale of Pollutant Source, Evidence of Human Exposure Pathway, Reliable Evidence of Health Impact, Number of People Potentially Affected, Level of Exposure, Numbers of children particularly at risk, Additional High Risk Elements. Together, these elements were analysed to produce this list of the most polluted in the cities in the world suffering from effects such as lead in the soil to toxins in the water and radioactive fallout in the air.