1. Barcelona: leaving the podium of Europe's most polluted cities

The Catalan capital ticks all the boxes when it comes to attractiveness: young, economically dynamic, touristy and boasting a growing European reputation for innovation and digital technology. However, when it comes to mobility, Spain's second-largest city is far from a star performer. According to Jordi Sunyer, Head of the Child Health Program at Barcelona's Institute for Global Health (ISG), pollution levels exceed the legal limits of the European Union and the World Health Organization on a daily basis. Over 50% of this pollution is directly linked to road traffic. Barcelona has one of the highest traffic densities in Europe, with almost 6,000 vehicles per square kilometer (2 times more than Madrid and 3 times more than London). In all, more than a million trips are made every day by private vehicle on the streets of the Catalan capital (600,000 by car and 350,000 by scooter and motorcycle)....