First, let me state that you can’t obtain the environmental sticker for your car unless it’s registered in Spain. These stickers are only valid for Spain, so any other stickers from countries like France, Germany, Austria, or Denmark have equivalents but still require a daily pass to drive through any major city (over 50,000 residents).
The two major cities requiring this pass are Madrid and Barcelona. Here’s the procedure to request these passes:
Madrid
In Madrid, there are two methods to request these passes:
Directly at their offices: This is for requests under 20 days, and you’ll need to present the following documents: the technical data sheet and vehicle registration certificate, plus your ID or passport to prove that you legally own the car.
Through their website: For requests over 20 days, you need to send an email to zbedistritocentro@madrid.es and attach the following documents: the technical data sheet and vehicle registration certificate, plus your ID or passport to prove that you legally own the car.
Here is an extract from the City Hall webpage translated into English, as they don’t have their webpage in English:
Low Emission Zone of Special Protection (LEZESP) District Center. Foreign or Diplomatic License Plate
Access to the Low Emission Zone of Special Protection (LEZESP) District Center will be permitted for these vehicles as long as they match the vehicle type and environmental characteristics of vehicles registered in Spain in accordance with the General Vehicle Regulations. Thus, access and circulation will be authorized under the same terms as for vehicles registered in Spain with equivalent type and environmental classification.
PROCEDURES
To determine the type and equivalent environmental classification of the vehicle according to industry classification, the vehicle’s technical data sheet and registration certificate must be provided. If the vehicle is national, a certificate from the DGT with the equivalent environmental classification category must be presented. The ownership of the vehicle must also be clearly proven.
It is recommended that this documentation be submitted at least 20 days before the intended access date, either via email to zbedistritocentro@madrid.es or in person by scheduling an appointment at the Specialized Authorization Management Office of LEZESP District Center, located at Calle Bustamante, 16.
Individuals (natural or legal persons) who were already registered and had access permission for the former «Madrid Central» Low Emission Zone do not need to reapply for registration and permits, provided they meet the access requirements for the LEZESP District Center.
Once the corresponding equivalence according to industry classification and environmental classification is obtained, the vehicle may access the zone according to the general or specific rules, depending on whether it is included in any groups with a special access regime to the LEZESP District Center. In such cases, the required documentation must be provided.
Barcelona
The City Hall’s webpage has all the information, procedures, and fees required to obtain the daily passes that will allow you to drive through the LEZ zones. Here’s the link: Barcelona LEZ Registration.