The first Low Emission Zone of Belgium has just become active within Belgium in Brussels (as of Feb 20: Antwerp as well). As of now you will receive a notification whenever you plan a route that goes through the low emission zone, unless you have added the pass indicating you have the permission to enter this zone. Also, without this pass set, Waze will route you around this zone. Should there be a route through this zone that is a lot faster, you will get a notification requesting whether you can take this route or not.
Please note that Waze will not stop you from entering the emission zone should you click the “drive now” button on the alert. Waze will simply guide you as if you have the pass at that point. This would probably only useful if you bought a day pass to enter the zone with your vehicle.
If you have the permission to drive through one or more emission zones, it is best to add these passes in the settings of the Waze app. There should be an obvious entry in the settings menu that allows you to set any zones you’re allowed to enter. Alternatively you can use the “add passes” button on the popup notification.
In order to see whether you are allowed to enter these emission zones, you will need to check lez.brussels for Brussels or lez.antwerpen.be for Antwerp. Please note that in 2020 the emission zone in Ghent will also become active. More information on that zone can be found at stad.gent. Sadly enough the rules on who gets to enter which zone were so complex we were unable to simplify this aspect with Waze. At the very least you’ll get to know whether your destination is located within an emission zone or not.