Catalonia Nitrogen Oxides Emissions Tax
The Catalonia Nitrogen Oxides (NOx) Emissions Tax came into force on 1 November 2014. It is an environmental tax administered by the Catalonia Tax Agency to help reduce air pollution caused by commercial aviation.
What is the Catalonia NOx Emissions Tax?
The Catalonia NOx Emissions Tax applies to NOx emissions from aircraft operating commercial passenger and cargo flights during the landing and take-off (LTO) cycle, which includes taxiing, take-off, and landing, at airports located in municipalities in Catalonia declared as Special Atmospheric Protection Zones. *
Positioning flights are not considered commercial flights for the purposes of the tax.
Certain flights are not subject to the tax, including medical flights, helicopter flights transporting sick persons, and public service flights such as traffic imaging, cartography and firefighting. Exemptions also apply to aircraft with an emission factor below 2 kg of NOx per LTO cycle and to flights operated in exceptional circumstances, such as emergency landings, operational problems at nearby airports, and specific humanitarian or charitable support operations.
Business jets may be subject to the tax when used for commercial passenger or cargo flights within the scope of the tax. The applicable NOx emission factor is determined based on the aircraft model, and the official emission-factor table includes various business-jet models.
How are NOx emissions and the tax calculated?
The taxable base is the amount of NOx, in kilograms, emitted by aircraft during the LTO cycle over the tax period, which is generally the calendar year. To determine the taxable base, the number of annual flights for each aircraft model is multiplied by the applicable NOx emission factor. The resulting amounts for each aircraft model are then added together.
Taxable Base (BI) = Σ (Annual flights × Applicable NOx emission factor)
NOx emission factors are determined using the EMEP/EEA Emissions Inventory Guide published by the European Environment Agency (EEA). If an aircraft model is not included in the guide, the emission factor declared by the manufacturer for the engine installed in that aircraft model is used. If this is not available, the emission factor of an engine with technically comparable NOx emissions is used. For helicopters, the applicable emission factors are those established by the Swiss Federal Office of Civil Aviation.
The current tax rate is €3.50 per kilogram of NOx. The gross tax liability is calculated by multiplying the taxable base by the tax rate.
Gross Tax Liability = Taxable Base (BI) × €3.50
A 5% reduction may apply based on the percentage of the taxpayer's aircraft operating at the relevant airport that are equipped with winglets (wingtip devices). If the reduction does not apply, the net tax liability is equal to the gross tax liability.
Who is liable for the tax?
The tax must be paid by airlines and by individuals or legal entities that operate or charter flights departing from an airport in Catalonia.
What are the obligations under the tax?
Operators liable for the tax must:
- Register with the Catalonia Tax Agency.
- Submit an annual electronic self-assessment using Form 990 and pay the tax between 1 and 20 February of the year following the relevant tax period. If the operator ceases activity, the tax return and payment must be made within one month of the cessation.
*Badalona, Barcelona, l'Hospitalet de Llobregat, Sant Adrià de Besòs, Santa Coloma de Gramenet, Castelldefels, Cornellà de Llobregat, Gavà, Martorell, Molins de Rei, Esplugues de Llobregat, el Papiol, Pallejà, el Prat de Llobregat, Sant Andreu de la Barca, Sant Feliu de Llobregat, Sant Joan Despí, Sant Just Desvern, Sant Vicenç dels Horts, Viladecans, Badia del Vallès, Barberà del Vallès, Castellbisbal, Cerdanyola del Vallès, Montcada i Reixac, Ripollet, Rubí, Sabadell, Sant Cugat del Vallès, Sant Quirze del Vallès, Santa Perpètua de Mogoda, Terrassa, Granollers, la Llagosta, Martorelles, Mollet del Vallès, Montmeló, Montornès del Vallès, Parets del Vallès, and Sant Fost de Campsentelles.
Last updated: 1 September 2026