They may have some of the dirtiest city skies in the planet, but at least the Chinese authorities are doing something about it. Check out the green, beautiful urban planning for the future of Beijing Central Business District:
I don't know if the lush gardens, the green public transportation, and the pedestrian and bike-friendly road network would help with their contamination problems, but they sure look pretty. SOM—the architects who won the Beijing Central Business District competition—say that it will help save a lot of money and resources:
The SOM plan defines new strategies for building municipal infrastructure and high performance buildings. Implementation of the plan could reduce energy consumption within the district by 50%, reduce water consumption by 48%, reduce landfill waste by 80%, and result in a 50% reduction in carbon emissions. Reduction in emissions from office buildings alone would equate to a reduction of 215,000 tons of CO2 per year, which is the equivalent of planting 14 million adult trees.