Dutch LEZs tightened for lorries from 1 January 2022.

There are currently 15 municipalities in the Netherlands that have an environmental zone for diesel trucks. These are: Amsterdam, Arnhem, Breda, Delft, The Hague, Eindhoven, Haarlem, Leiden, Maastricht, Maasvlakte Rotterdam, Rijswijk, Rotterdam, 's-Hertogenbosch, Tilburg and Utrecht.
As of 1 January 2022, you will encounter a purple environmental zone in those municipalities. In purple environmental zones, only diesel trucks with at least emission class 6 are allowed. Diesel trucks with emission class 5 and lower are not allowed in here. The emission class is a number that indicates how clean your vehicle is. The higher the number, the cleaner your vehicle. 
For more information on where to buy stickers go here.

Source: Pixabay