1. Milan, Italy

3.  In Milan, cars need a permit to enter the city centre. Only residents and some employers can obtain a permit, so very little traffic now drives in or out. Nearly everyone parks on the edge of the restricted area and heads for the centre on foot.

4.  As a result, Milan now has many pedestrian-only shopping streets, and this has led to an increase in shopping in the city centre. Grass and tree have been planted, and many other improvements have also been made.

5.  The permit scheme is now recognised as a great success. The scheme is unique to Milan, but it is thought that similar car bans and pedestrian scheme will have spread to other Italian cities by the end of the decade.