SCHEDULES  SCHEDULE 1  Administrative procedures  Article 70(1)  1. —(1) The procedures specified in this Schedule summarise administrative roles and  responsibilities of the persons involved in implementing Parts 2 and 3 of this Order. This Schedule  provides a list of activities, and the associated date by which the activities must be completed.  Compliance periods and timeline  2021-2023 period  Table 1  Details of compliance timeline for 2021-2023 period  (2) During the period of 2021-2023, aeroplane operators and Regulators must comply with the  requirements according to the timeline in Table 1, where applicable.  Timeline  Activity  To 31st December 2021 The aeroplane operator must monitor, in  accordance with Chapter 2 of Part 3 of this  Order, CO$_{2}$ emissions for 2021 from  international flights.  To 31st May 2021 The aeroplane operator must compile 2020 CO$_{2}$  emissions data to be verified by a verification  body, in accordance with Chapter 4 of Part 3 of  this Order. 31st May 2021 The aeroplane operator and the verification  body must both independently submit, upon  authorisation by the aeroplane operator, the  verified Emissions Report and associated  Verification Report for 2020 to the Regulator in  accordance with article 35(3).  1st June 2021 to 31st August 2021 The Regulator must conduct an order of  magnitude check of the verified Emissions  Report for 2020 in accordance with article  35(4) including any filling in of data gaps in  case of non-reporting by aeroplane operators in  accordance with article 37(6) and (7). 30th June 2021 The Secretary of State must notify ICAO of any  change in the decision by the government of the  United Kingdom to voluntarily participate, or to  discontinue the voluntary participation, in the  applicability of CORSIA’s offsetting  requirements under Part II, Chapter 3 of  Volume IV of Annex 16 to the Chicago  Convention from 1st January 2022 in  accordance with article 7(1). 1st August 2021 The Regulator must obtain and use the ICAO  document entitled “CORSIA States for Chapter  3 State Pairs” applicable for the 2022  compliance year.  31st August 2021 The Secretary of State must submit required  information regarding CO$_{2}$ emissions for 2020  to ICAO in accordance with article 33(3). 34