The International Conference on Compressors and their Systems is 3-day conference organised by the Centre for Compressors Technology at City, University of London. It will take place on the 6th - 8th of September 2021. The programme will be more cohesive this year by the inclusion of industry sessions on high-importance topics in addition to the traditional keynote addresses, research and technical papers, podium papers and discussions. This will provide a platform to identify current challenges and provide the essential content and direction to shape future research.