A bio-economy is grounded on the use of renewable, biotic resources. A circular economy, on the other hand, emphasises resource conservation in general. When one refers to a circular bio-economy, one gets the best of both these worlds, so to say. It is a set of ‘many-to-many’ relationships, which are perfectly symbiotic at best. In the longer run, in a circular bio-economy, one can expect economies of scale and scope. It follows that one would then have accelerated the pace of sustainable development-that never-ending journey towards the elusive goal of ‘sustainability’. It goes without saying that urban metabolism in a circular bio-economy will metamor-phose into something extremely transformative-for combating climate change and its repercussions, as well as a host of other challenges, attaining several Sustainable Development Goals in the process. Well-begun is half done, and here is where cities ought to learn from each other. All new ventures can be inspired by the paradigm of a circular economy (bio-economy wherever that is possible), while simple symbi-otic relationships amongst diverse entities within a city can be uncovered with some out-of-the-box thinking. Needless to state, as all know, challenges lurk where oppor-tunities abound to supplant the current ‘take-make-use-dispose’ culture of a linear economy with a beneficial ‘grow-make-use-share-partake-restore’ paradigm of a circular bio-economy. Smart cities will be the ones that avail of these opportunities and strive towards the ‘more from less’ goal.