The diploma creates an exceptional regime regarding the operation of aircraft at Humberto Delgado Airport, in Lisbon, during the time period "strictly necessary to ensure the process of changing the air traffic management system, starting on October 18 and not extending beyond" 28 November 2022.

The limit of night flights is waived by the ordinance, allowing the operation of aircraft at Humberto Delgado Airport between 00:00 and 2:00 and between 5:00 and 6:00.

In the first week, between 18 and 23 October, they cannot exceed 168, in the second week 86 flights, in the third 75, in the fourth 45, in the fifth 30 and in the last week, between 21 and 28 November, 20 more flights.

The diploma also introduces the obligation to communicate to the population, informing about the urgency and exceptionality of the process, the maximum temporal duration of the derogation, the identification of the areas over flown, weekly reports indicating the number of flights covered by the derogation and the mitigation measures adopted.

The population must also be informed of the final report on the implementation and monitoring of the migration process of the air traffic management system.

The ordinance, which comes into force on Tuesday, was published despite protests from environmental associations, such as Zero, which considers it “illegitimate” that in the name of updating an air traffic control system, “the citizens of Lisbon and Loures are called to be sacrificed with intolerable night time noise levels".

In July, the environmental association Zero denounced that noise levels at Lisbon airport exceed legal limits and warned that the night flight restriction regime is also not complied with, citing measurements taken in the week starting July 11 and which pointed to a total of 140 movements between 00:00 and 06:00.