What does sustainability really mean? From architecture and automobiles to product design and fashion, we tackle the issue of sustainability in design. Architect Tom Kundig and Rama Gheerawo of London’s Royal College of Art tell us what sustainability means to them and Benjamin Hubert, head of design agency Layer, explains how he balances sustainable values with commercial interests. Plus: Monocle’s Jamie Waters brings us his picks of the sustainable items found in the fashion cupboard of Midori House.