Some countries (Éire or Ireland as the outsiders call it)  both CO2 and NO2 emission data is required for customs declarations.  Usually that information is for used European cars, made in various European countries and exported to Japan.  Hidden away in the depths of the Japan’s Ministry of International Trade and Industry (miti) homepage is the data, usually in tables and usually in Japanese.

Emission data example of the Mistubishi mirage
Emission data example of the Mistubishi mirage

If you are looking for data to help for your import or need it to be translated, get in touch.