Vehicle and engine emission standards are issued jointly by the Ministry of Environmental Protection (MEP) and the Standardization Administration of China (SAC), though MEP is in charge of developing, drafting, and approving the standards. In addition to National Standards, which are mandatory nationwide, Environmental Standards may apply to industries that have an impact on the quality of the environment, and Local Standards may be issued by local governments. The following naming conventions (prefixes) apply to the various types of regulations and standards:
- GB—mandatory national standards,
- GB/T—recommended national standards,
- HJ—environmental standards,
- HJ/T—recommended environmental standards,
- BJ (Beijing) and SH (Shanghai) are example local standards.
The first emission regulations for motor vehicles became effective in the 1990s [Regulation GB 14761]. Chinese standards, up to and including China 6a, are based on European regulations, adopted with a certain time delay. Beijing proposed standards for light-duty vehicles based on US Tier 3 limits but appears to be prepared to withdraw this proposal in favour of Euro 6 based standards proposed by the MEP in May 2016 once the later are formalized.
Once a national standard has been issued, cities and regions in China may implement the standard in advance of the nationwide implementation dates, conditional on receiving approval from the State Council. In some cases, special approval can be granted to cities or regions to implement a stricter standard before the national standard has been released. Large metropolitan areas, including Beijing and Shanghai, Guangzhou, and some other cities have adopted more stringent regulations on an accelerated schedule, ahead of the rest of the country. Beijing implemented Euro 4 standards for light-duty vehicles in 2008 (the year of the Beijing Olympics) and Euro 5-based standards from 2013. Many cities in China use a system of colored labels attached to the vehicle to identify which vehicles meet the required emission standards.
Regulated Engines and Vehicles
Emission standards have been adopted for the following categories of new engines and/or vehicles:
- Cars and Light Trucks
- Motorcycles and Mopeds: China IV emission standards for motorcycles  and mopeds  were adopted in 2016 and become effective from 2019.07.
- Heavy-Duty Truck and Bus Engines
- Nonroad (Off-Road) Diesel Engines
- Marine Engines
Furthermore, fuel consumption standards for light-duty vehicles have been effective since 2005.