Dieselgate casts doubt over low emission zones

There is no feigning ignorance for car drivers entering the Dutch city of Rotterdam via the highway from the northeast. The sign announcing a “low emission zone” that bans dirty cars is spelt out in Dutch, French, Polish, English, and German.

Since the beginning of the year, the second-largest city in the Netherlands is banning all petrol cars that are older than July 1992, and all diesel cars older than 2001.

The local government announced on November 11 that the low emission zon...