Smog

The term "smog" first appeared at the turn of the 20th century to describe the veil of smoky fog that covered British towns due to the era's significantly polluting industrial sectors. Since then, the same thing has happened in a lot of big cities with a lot of industrialized areas.

Due in large part to the extensive coal burning in China, the country is infamous for having terrible air quality. It was discovered in 2019 that China's solar energy output had decreased by 11% to 15% as a result of the dense haze blocking the sun's rays from reaching solar panels. At the end of 2016, cities like Beijing had an eight-day stretch of extremely high pollution levels that made the sky murky and prevented the sun from shining.

Beijing had been dealing with the issue for many years, and in 2014 the city put policies in place to address it. In time for the Olympic Games in 2021, Beijing was finally able to achieve its own state-set air quality criteria for the first time ever.