What does China 6 mean?

[BraydenMarie]

China 6 refers to the China 6 Emission Standards, which is the national sixth-stage motor vehicle pollutant emission standard established to prevent motor vehicle pollution emissions and improve ambient air quality. Under the China 6a emission standards, the carbon monoxide emission limit for gasoline and diesel vehicles is set at 0.5g per kilometer, with China 6a generally adopting the minimum limits of the China 5 standards. China 6b represents the true China 6 emission standards, implementing stricter control over nitrogen oxide emissions with significantly reduced values compared to previous standards, while also imposing limits on nitrogen dioxide emissions. The China 6 emission standards serve as an upgraded version of the current China 5 standards, featuring more stringent limits on CO, THC, NMHC, NOX, and PM emissions compared to China 5, along with newly added regulations on PN emissions.