Parallel to the ongoing depletion of natural resources and the population growth that puts ever-growing pressure on the environment, the past decades have seen many promising developments. One of the key developments is the idea of a circular economy that stems from the Cradle to Cradle framework discussed in the previous chapter. The term circular economy relates to the role of natural diversity as a characteristic of resilient and productive systems and underscores the importance of the production process in which by-products are used as a resource for new products. This process is known as end-of-waste (EoW) criteria with environmental protection and public health, take-back requirements and extended producer responsibility as a starting point.