Part I of Volume IV of Annex 16 contains definitions, abbreviations and symbols. Part II, Chapter 2 contains Standards, Recommended Practices and guidelines for monitoring, reporting and verification of an aeroplane operator’s CO2 emissions. Part II, Chapter 3 contains Standards, Recommended Practices and guidelines on an aeroplane operator’s CO2 offsetting requirements that can be reconciled using Emissions Units generated by eligible programmes under Chapter 4. The relevant applicability requirements to an aeroplane operator engaged in international air navigation are specified in the individual Chapters of Volume IV of Annex 16.