A circular economy (also referred to as circularity or CE) is a model of resource production and consumption in any economy, which involves sharing, leasing, reusing, repairing, refurbishing and recycling existing materials and products for as long as possible. The concept aims to tackle global challenges such as climate change, biodiversity loss, waste, and pollution by emphasizing the design-based implementation of the three base principles of the model. The three principles required for the transformation to a circular economy are: designing out waste and pollution, keeping products and materials in use, and regenerating natural systems." CE is defined in contradistinction to the traditional linear economy. The idea and concepts of a circular economy have been studied extensively in academia, business, and government over the past ten years. It has been gaining popularity because it can help to minimize carbon emissions and the consumption of raw materials, open up new market prospects and, principally, increase the sustainability of consumption.At a government level, a circular economy is viewed as a method of combating global warming, as well as a facilitator of long-term growth. CE may geographically connect actors and resources to stop material loops at the regional level. In its core principle, the European Parliament defines CE as, "a model of production and consumption, which involves sharing, leasing, reusing, repairing, refurbishing and recycling existing materials and products as long as possible. In this way, the life cycle of products is extended." By the year 2050, 9.3 billion tonnes of CO2 equivalent (equal to all current emissions from transportation), can be reduced by implementing circular economy strategies in five sectors: cement, aluminum, steel, plastics, and food.In a circular economy, business models play a crucial role in enabling the shift from linear to circular processes. Various business models have been identified that support circularity, including product-as-a-service, sharing platforms, and product life extension models, among others. These models aim to optimize resource utilization, reduce waste, and create value for businesses and customers alike, while contributing to the overall goals of the circular economy. In a linear economy, natural resources are turned into products that are ultimately destined to become waste because of the way they have been designed and manufactured. This process is often summarized by "take, make, waste". By contrast, a circular economy aims to transition from a 'take-make-waste' approach to a more restorative and regenerative system. It employs reuse, sharing, repair, refurbishment, remanufacturing and recycling to create a closed-loop system, reducing the use of resource inputs and the creation of waste, pollution and carbon emissions. The circular economy aims to keep products, materials, equipment and infrastructure in use for longer, thus improving the productivity of these resources. Waste materials and energy should become input for other processes through waste valorization: either as a component for another industrial process or as regenerative resources for nature (e.g., compost). The Ellen MacArthur Foundation (EMF) defines the circular economy as an industrial economy that is restorative or regenerative by value and design.Circular economy strategies can be applied at various scales, from individual products and services to entire industries and cities. For example, industrial symbiosis is a strategy where waste from one industry becomes an input for another, creating a network of resource exchange and reducing waste, pollution, and resource consumption. Similarly, circular cities aim to integrate circular principles into urban planning and development, fostering local resource loops and promoting sustainable lifestyles among their citizens. Less than 10% of economic activity worldwide in 2022 and 2023 has been circular. Source: Wikipedia (en)