How to Distinguish the Symbols for National Emission Standards?

[MirandaFitz]

It's actually quite simple to distinguish the national emission standard of a vehicle—it's represented by Roman numerals: I–1, II-2, III-3, IV-4, V-5, VI-6, VII-7… 'V' stands for five. If 'I' is to the left of 'V', it means five minus one (IV). If 'I' is to the right of 'V', it means five plus one (VI). The symbols for National Standards 1 to 6 are I, II, III, IV, V, and VI, respectively. On July 1, 2000, China introduced the National Standard 1 emission regulations for the first time. Since it was based on European emission standards and aligned with international norms, Roman numerals were adopted for the symbols from National Standard 1 to 6. New emission standards have been introduced every few years since then.