"APEC Blue" (APEC蓝), a new term coined by smog-beleaguered citizens, refers to clear blue skies Beijing experienced during the APEC convention in the capital on Nov.1-12, 2014.
During that time, Beijing had four days straight of excellent air quality and an average concentration of PM 2.5 of only 43 micrograms per cubic meter. The good air quality during the diplomatic summit greatly impressed local residents, so the government decided to make "APEC blue" normal in Beijing.
While the term delights in embracing the ephemeral blue sky, it shows concern that such a blue sky is only a result of a face-saving project. Now it has become a word for a mirage.