It was blue sky all week during APEC 2014, then on the last day before I headed for Seoul, it was wheels-up for Air Force One and right back to smog...
Also, I've heard from locals that they're starting to relocate dirty industries to nearby cities that foreigners tend not to visit. I visited one, and there were a few days of pretty bad smog (but blue skys some days, too).
It is a shame though Beijing is mostly exporting their pollution elsewhere. China as a whole is still building more of those polluting coal fired power plants. China plans to increase their coal-fired generation capacity by nearly 20% over the next few years. Coal usage (and coal CO2 pollution) will increase and is projected to remain flat through 2030. Though the pollution will be out of sight from major cities. Guess they can't get enough of that cheap coal electricity.
China is a very big ocean liner, so it takes a long time to change direction, but it is definitely changing.
`In October 2014, the European Council called for all EU countries to achieve interconnection of at least 10% of their installed electricity production capacity by 2020. This means that each country should have in place electricity cables that allow at least 10% of the electricity produced by its power plants to be transported across its borders to neighbouring countries. 17 countries are already on track to reach that target by 2020, or have already reached the target, but more interconnections are needed in some regions.`
I am from southern Poland, where in winter time some regions experience visibility range of less than 200m due to smog.
This is due to many factors, including people burning trash to heat their homes, industrial pollution, building over natural green corridors, as well as simply local geography (lots of valleys and basins)
It looks like they've learned from the West.