Americans buy, on average, almost 70 items of clothing a year. And many of those garments are worn just seven to ten times before being thrown away. This breakneck consumption of clothes is only possible because of fast fashion, a system in which clothing is made quickly, sold cheaply, and seen as pretty disposable. Dana Thomas, author of “Fashionopolis: The Price of Fast Fashion and the Future of Clothes,” walks us through the origins and effects of fast fashion.