Measure to fight pollution take years to pay off. China had in fact been battling bad air for decades before cleaner skies became tangible. By the 2008 Olympic Games, pollution abatement equipment had been mandated and installed on the vast majority of its thermal power plants. This was technology that removed up to 95 percent of Sulphur Dioxide emissions. Nitrogen oxide-removing tech was next to become widely installed.

Through a combination of closing or upgrading coal-fired brick kilns and other polluting industries, enforcing strict vehicular emissions standards, transitioning to cleaner energy sources like natural gas and renewables, and promoting electric vehicles (EVs), Beijing’s air was gradually, not suddenly, cleaned.

In 2014, China updated its environmental protection law to give local authorities the power to detain company bosses who failed to complete environmental impact assessments. The law also removed limits on the fines that firms could be subject to for breaching pollution quotas.

Very interesting article on the steps they took to reduce air pollution! The last paragraph (emphasis mine) really shows how serious they take it and how serious other countries should as well.