Air carriers having operated at least 80% of slots in their allocated series of slots during a scheduling period are entitled to retain the same series of slots in the next equivalent scheduling period. A series of temporary rules allowing airlines to retain historic slots despite not using their slots according to the 80% use rate were in place from 1 March 2020 to 25 March 2023 on grounds of reduced air traffic levels due to the COVID-19 pandemic. As of 26 March 2023, such slot relief rules are no longer in force. However, due to a 2022 amendment to the Regulation, the European Commission is empowered to lower the use rate from 80% by delegated act if air traffic falls below 80% of 2019 levels for two consecutive weeks due to an epidemiological situation or as a direct effect of Russia’s war of aggression against Ukraine.