--FILE--Tourists visit the promenade on the Bund to view the cityscape of the Lujiazui Financial District with the Oriental Pearl TV Tower, tallest left, the Shanghai Tower, tallest right, and other skyscrapers and high-rise buildings in Pudong, Shanghai, China, 26 September 2016. August saw Shanghai record its best air quality for five years, with average PM2.5 density over the month recorded at 19 micrograms per cubic metre, down 52 percent on the average for August 2015. 'A moderate climate and a good distribution of air, ' were the key factors to this drop, according to Shanghai Daily. However it is no secret that another crucial factor was September's G20 summit in Hangzhou and the efforts that were made to ensure there were blue skies for the occasion. It has been reported that 255 factories in Shanghai closed especially for the summit, including many operated by large China petrochemical company Sinopec, which estimated its production was down by over 50 percent during the period.
