The Spanish Law on Climate Change and Energy Transition requires doing so.

Spanish cities with more than 50,000 inhabitants must create low-emission zones to reduce polluting emissions in transport. 
The Regulatory Ordinance for the Low Emission Zone of the City of Fuenlabrada has been approved and will come into force on July 15, 2024.

Vehicles with an environmental badge B or better can enter the zone.
There are exemptions for some vehicles and certain groups of people.

Picture source pixabay.