A general view of Beijing city viewed from the Western Mountains on December 11, 2007 on the outskirts of Beijing, China. An environmental campaign titled 'Guard The Blue Sky' was launched on December 10 with the aim of achieving 245 days in 2008 which would be deemed to fall within acceptable levels of pollution. Sources of pollution in and around the city are targeted as the city prepares to host the 2008 Beijing Olympics.

