The third national standard is the third-stage automobile emission standard in China.

In the third stage, the national emission standard is equivalent to the European emission standard, that is to say, the content of exhaust pollutants is equivalent to the European emission standard, but the difference is that new cars must be equipped with OBD (on-board self-diagnosis system). The on-board self-diagnosis system is characterized by adding detection points and detection systems, and setting oxygen sensors at the inlet and outlet of the three-way catalytic converter. The implementation of Euro III emission standards can control compliance by monitoring vehicle emissions in real time.