From China Digital Space
APEC lán APEC蓝
In an effort to cut air pollution by 40% for the APEC summit, the city gave students and workers a bonus "Golden Week" holiday, halted factory and construction work, enacted alternate driving days for even- and odd-numbered license plates, and even put a temporary stop to barbecues and cremations. The skies were indeed bluer, but the extent of the improvement was tough to measure. Air quality data from the U.S. embassy, available to denizens on the China Air Quality Index app and considered more reliable than municipal reports, was censored. "APEC blue" thus describes a hue reserved for foreign dignitaries that cannot be quantified:
Songyingjie (@宋英杰): It's said that Beijing only had two cases of smog this year: once before APEC, and once after. (November 19, 2014)
Caijingnüjizhebuluo (@财经女记者部落): #APECblue tells us: It's not that the government can't do it, it's that you aren't important! (November 6, 2014)
Government efforts to temporarily clean up air pollution ahead of high-profile international events were prominently used during the 2008 Beijing Olympics, and have since been increasingly used in other cities across China. In December 2016, as many Chinese cities were experiencing toxic air pollution levels, a study showing that quick fixes are often followed by the intense deterioration of air quality was publicized by the South China Morning Post.
See also Chai Jing blue.