Art in one of Stockholm's underground stations Flickr/Tobias Lindman Some of the world's leading cities are plagued by traffic jams and late trains, while others run like clockwork.

So which cities have the best infrastructure?

The 2017 Quality of Living Survey from human resources consulting firm Mercer, released last week, ranks cities according to — among other things — the quality of their public infrastructure.

The ranking is based on public transportation, traffic congestion, and the range of international flights from local airports, electricity supply, water availability, telephone and mail services.

Take a look at the 21 cities with the best infrastructure and a glance at how public transport operates in different locations across the world.