The Paris Olympics aims to be the greenest Games in history. Here's how

Paris will host many events in pre-existing venues to avoid constructing new ones. Cyclists will race at the Saint-Quentin-en-Yvelines velodrome, built 10 years ago. While the Stade de France will host athletics. Its lighting is being converted from oil to biofuels, saving 13,000 tonnes of CO2 emissions.