This report aims at sharing knowledge relevant for sustainabili- ty-oriented studies and actions in the Dutch apparel sector, with a focus on clothing volumes. The apparel industry is said to be one of the most polluting at a global level; however, we nd that dis- cussions of its environmental challenges or the actions needed to tackle them are often based on super cial or unreliable information. This information is frequently disseminated by word of mouth and non-scienti c texts and nally accepted as valid. Moreover, some actors working on practice-based solutions for the environmen- tal challenges of the apparel industry build solutions and projects based on these ‘facts’. As a result, these actors risk focussing on topics that are not as critical or relevant as was originally thought. Clear, reliable data is needed to pinpoint the true challenges and bottlenecks within the fashion system.