A new environmental zone in force since early this year in Rotterdam has halved the number of severely polluting cars entering the city in just one month.

Every day up to 700 000 vehicles enter Rotterdam, of which 1.18 per cent (some 13 000 cars) were older models whose emissions were considered to be extremely harmful.

From 1 January 2016 the Dutch city announced that such vehicles would be banned from entering. Since then, the number of dirtier cars in the city has dropped to 0.66 per cent,