China is one of the biggest polluters on the planet. The country joined the Paris Agreement, but then ratcheted up coal-fired electrical generation when its economy slowed over the past couple of years.
Now it appears that Chinese industrial pollution in cities like Guangzhou, Shanghai and Chengdu is running between 20% and 50% of normal for this time of year. If you want to see greenhouse gas emissions drop, this might be great, but it also means something else. Traffic and industrial production are likely operating between 50% and 80% below capacity, and this is at a time when factories increase activity to make up for slow production during the Lunar New Year.
The lack of pollution gives lie to the Chinese claim that their economic engine is coming back online.