An aerial photo taken during a polluted day in Shenyang, Liaoning province.
Two people ride during heavy smog in Lianyungang, Jiangsu province.
A tree sits between two buildings that tower through the thick smog in Jinan, Shandong province.
A view from the Jin Mao Tower in the Puxi district of Shanghai amid heavy smog.
A man cooks in open air during a "red alert" day in Hebei province.
Smog looms over the city of Tianjin, in northeastern China.
Bike riders wear masks to help filter the air they breath.
This woman and a young boy also choose to wear masks while in Jillin.
Masks can help filter out a particulate matter called PM 2.5, which can get stuck in the lungs and lead to conditions like asthma and chronic lung disease.
Some take more drastic measures to guard themselves from the pollution, such as this man wearing a full-on respirator in Beijing.
Everyday work doesn't stop in the smog — here, workers clean the exterior of the Shanghai World Financial Center.
People are seen on the street in smog during a polluted day in Shenyang, Liaoning province.
A woman wears a mask on a polluted evening.
Boats pass along the Huangpu River next to the financial area of the Pudong New District amid heavy smog in Shanghai, China.
Residential buildings are shrouded in a haze in Shenyang.
The lights of downtown Shanghai appear dim due to the haze.
In Harbin, a traffic policeman has to help navigate commuters since they can barely make out the headlights in front of them.
The smoke billowing from a nearby steel plant doesn't seem to bother this girl as she reads on her balcony in Quzhou.
A statue of China's late Chairman Mao Zedong stands tall in Shenyang.
Despite the poor air quality, cleaners work along the median of a main road in central Beijing.
People walk on the Bund, a waterfront area near the financial district of Pudong in downtown Shanghai.
A woman strolls through polluted air in front of a construction site of a residential compound in Wuhan.
Smoke from a refinery's chimneys and cooling towers rises above the skyline in Ningbo.
A woman walks across the street during a particularly smoggy day in Changchun.
Citizens walk across a bridge, their line of sight extremely short due to the thick smog.
A woman makes her way through traffic in Changchun.
High-rise buildings are shrouded in heavy haze all the way up to the top of the Qingdao development zone.
The tops of these residential compounds in Wujiaqu just barely make it above the smog.
An electronic screen's brightness shines through this smog in Shenyang.
