smog
Images capture the ebb and flow of China's climate crisis.
For many Beijing residents face masks have become a routine cold-weather accessory.
You have to see it to believe it.
Air pollution is now at hazardous levels in the Chinese capital.
WHAT'S HAPPENING
Orange alert issued as air pollution soars 15 times over safe limit.
Environmental and public health groups say the new standard is a "betrayal" of clean air protections.
If things don't change, the death toll will double.
A former EPA official is working with BP on a plan to undermine new smog standards.
The city will limit the number of vehicles on the streets and shut factories.