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Oslo, Norway

There is no industry in Oslo, so the city has good air quality in the summer, though vehicular and heating emissions lower that quality in the winter. The city fares well in waste management, following The Waste Management Strategy 2006 – 2009, which diverts organic waste for treatment in a biogas plant, which is then transformed into fuel for city buses. Also, methane gas from the landfill is collected and converted to electricity.

Manchan | Photodisc | Getty Images