'Cities are leading the fight against pollution'

Olivier Blond is president of the French environmental group "Respire" ('Breathe'), which calls for action on air pollution. In the past few weeks, dozens of cities around the world have registered peak pollution levels, and more precisely, high levels of particle matter, fine particles that go into our lungs when we breathe. Those cities include more than 20 in China, plus New Delhi and Kolkata in India but also Madrid and here in Paris. So what can be done to fight air pollution?