What do National V and National VI mean?

[MacJordan]

National V is China 5, and National VI is China 6. National V stands for the National Fifth Stage Emission Standard for Motor Vehicle Pollutants, while National VI stands for the National Sixth Stage Emission Standard for Motor Vehicle Pollutants. Both refer to the emission standards for vehicle exhaust. The emission control level of National V is equivalent to the European Stage 5 emission standard, imposing stricter limits on nitrogen oxides, hydrocarbons, carbon monoxide, and particulate matter emitted by motor vehicles. From National I to National IV, each upgrade in the standard reduces vehicle pollution by 30% to 50%. The National VI emission standard improves upon National V by 40% to 50%, reaching a level comparable to that of the United States, making it one of the strictest emission standards globally. The National VI emission standard is implemented in two phases: National VIa and National VIb, with National VIb being even stricter than National VIa.

[VanJackson]

As someone who frequently deals with vehicle management offices, I find the National V and National VI standards quite important. National V refers to China's fifth-stage emission standards for motor vehicle pollutants, while National VI is the stricter sixth stage. The rollout of National V vehicles started in 2017, and after 2020, most new cars basically comply with National VI standards. The difference is substantial—just like upgrading a phone's operating system, National VI vehicles are equipped with more advanced exhaust treatment systems, reducing PM2.5 emissions by more than half compared to National V. Currently, some cities impose traffic restrictions where National V vehicles cannot enter urban areas, so buying a used car requires special attention to the emission label color. When I upgraded my car, I specifically chose a National VIb version, as it could fetch an extra ten thousand yuan when reselling later.

[Anastasia]

Having worked on so many engines in the repair shop, the most visible change with emission standard upgrades is the extra pipes added to vehicles. China V vehicles use a three-way catalytic converter to treat exhaust, while China VI models require an additional particulate filter—like putting a double mask on the exhaust pipe. During annual inspections, China VI vehicles face stricter data requirements; even a 0.1% deviation in oxygen sensor readings could lead to failure. Last time, a China V car tried to cheat OBD detection with a simulator, only to get caught by the infrared spectrometer during inspection, wasting 2,000 RMB on modifications. When buying used cars, always check the environmental protection website first—some 2016 models are fake China V compliant.

[SanSawyer]

Brothers in the transportation business should pay more attention to this. Many provinces now prohibit National IV trucks from entering highways, while National V trucks can still hold on for a few more years. Last year, I chose a National VI heavy-duty truck when replacing my vehicle. It consumes 30% more urea than a National V truck, but I don’t have to worry about fines from sudden environmental inspections. The most critical thing is the emission standard letter on the vehicle registration certificate: National V is marked as V, while National VI is marked as VI. Once, when helping a friend transfer ownership of his truck, his National V truck was mistakenly marked as VI on the certificate. The vehicle management office required me to bring the announcement catalog to correct it. For logistics companies buying new trucks, it’s recommended to go directly for National VI b, as regions like Beijing-Tianjin-Hebei have already started restricting National V trucks from entering urban areas.

[LouisAnn]

Attention to car enthusiasts who love modifications, emission standards directly affect the tuning space. My National V BRZ with a straight pipe exhaust received three warnings, and a friend's National VI Civic with a modified downpipe immediately triggered a fault light. Nowadays, new cars are equipped with GPF (Gasoline Particulate Filters), and reckless exhaust modifications not only cause trouble during annual inspections but may also lead to engine torque limitations. A car parts shop owner once taught me to tweak the ECU to bypass OBD detection, but getting caught during a roadside inspection could result in the car being impounded. It's better to consider purchasing a National V performance car from around 2016, like the GTI or Focus ST, which have mature modification solutions. Last year, even agents could handle the inspection for these models.