pollution in paris

Yesterday I noticed for the 2nd day in row it was free to ride the metro in Paris. On December 6th my son and I joked that they made it "libre access" because it was his birthday, but here we are again on the 3rd consecutive day and yes the metro and all public transportation for that matter is free for Paris and the banlieu/ suburbs. As with most metropolitan cities the culprit is the diesel and as there is not enough wind we are getting the pollution coming close to us on the ground. Who[...]