A combination of 225 photos taken at the same angle from a building on the Third Ring Road between 8 and 9 am from March 1, 2012 to March 5, 2013 record the different shades of blue and grey skies that shroud the Chinese capital. Beijing has been suffering dangerous levels of pollution in the past year and the city has promised to take effective measures to curb the choking smog. [Photo/CFP]
Special: Air quality suffers due to smog