10 years earlier, the most unpleasant weather in Beijing would be only the sandstorm, which mainly occurs only during spring and annoys all citizens in April or May. The Gobi deserts are the main source of the sand.
These years, the sandstorms were not the worst weather around the year, we are more annoyed by the smog (or haze), which could come at anytime during the year, especially winter and spring. As I clearly remembered, the year 2017 started with a clear sky, however, the second day was covered by haze unfortunately.
In November, 2014, the APEC (Asia-Pacific Economic Cooperation) summit was held in Beijing. During the meeting, Beijing enjoyed attractive clear sky and good weather for almost one whole week. During that time, one derisive buzzword called “APEC蓝” (APEC Blue) was widespread nationally, which is defined as “something wonderful but also fleeting”, because we all knew that this scene was somehow “artificial”. Before the summit, the government forced a lot of industry around Beijing to stop production, especially those factories which had high-energy demand, such as coal, steel production and heating supply. Therefore, the air quality problem is not a irresolvable issue, as long as there are real policies and actions.
Besides those large summit, the weather in Beijing is highly determined by the wind direction: If the wind comes from the north (which contains cold air), the weather will be nice; however, if the wind comes from the south (which contains warm air and some polluted industries are located in southern provinces), the air quality would be bad.
“Economic growth or the environment?”. This is always a problem in China. For the central government, they definately want to maintain the annual economic increase as well as ideally keep the environment situation well, but some governors in small towns or countryside do not really care about it as most of the highly-polluted and energy-demanded factories in small places contribute a large amount of the tax income of the town.