The so-called national standard, that is, before the implementation of national 1 emission, has already required the smoke of vehicles and engines, but there is no real national standard, just a formulation.
Yellow label vehicle refers to a gasoline vehicle whose pollutant emission reaches the national 1 or above technical requirements and standard limits at the time of first registration, and a diesel vehicle that reaches the national 3 or above standards.
So country 0 and yellow label are not equal.