ICAO CORSIA Implementation Element is reflected in the ICAO document entitled "CORSIA States for Chapter 3 State Pairs" referenced in Annex 16, Volume IV.
The third edition of this ICAO document has been approved by the ICAO Council and contains the States that participate in CORSIA from 1 January 2023 and is available here:https://www.icao.int/environmental-protection/CORSIA/Pages/state-pairs.aspx
For a given year (starting in 2021), the States included in ICAO document entitled "CORSIA States for Chapter 3 State Pairs" define the State pairs subject to CO2 offsetting requirements in CORSIA in that year.
