The pollution is Beijing has gotten so bad that it is not only so thick you can't see more than a few feet in front of you, breathing masks are needed because the air quality is actually rated as hazardous by the government. As described here.
The Asia Pacific conference is coming to Beijing soon, so they have planned to shut down, or partially shut down, factories and car traffic in and around the city in order to reduce the pollution for the arriving world leaders. As described here.
Those who question whether humans effect the environment, here is a perfect example of humans altering their environment.