As the first dieselgate trials get underway we examine the scandal's impact on Volkswagen. The former chief executive of its subsidiary Audi faces trial in Germany, and denies any wrongdoing. Jack Ewing of the New York Times in Frankfurt wrote Faster, Higher, Farther: How One of the World's Largest Automakers Committed a Massive Fraud, and reminds us how the story emerged. Ferdinand Dudenhoffer of the Centre for Automotive Research in Duisberg tells us boardroom culture at Volkswagen has now seen a major shift. VW is now focusing on electric vehicle technology, and Peter Carlson, chief executive of Swedish battery manufacturer Northvolt explains how the two firms are collaborating. And EU environment commissioner Virginijus Sinkevicius, discusses how the threat of punishment over emissions standards is impacting carmakers' behaviour. Also in the programme, US presidential candidates Donald Trump and Joe Biden have held their first head-to-head debate ahead of November's election. We ask Alex Flint, executive director of the Alliance for Market Solutions in Washington, how much we learned about the two candidates' future stance on the economy and the environment. Plus, on International Podcast Day, we look at the future of the rapidly developing audio medium with New York-based Zibby Owens, who presents her own podcast interviewing authors about their books.