## 2 Literature Review
### CE Implementation  
From a systematic perspective, the implementation of CE has several practical aspects that vertically comprise the micro level, meso level, and macro level. These three levels are interdependent [47; 48]. Research on barriers to the adoption of circular business models, e.g., [PERSON] et al. [49], has focused on micro-level initiatives. For a focal firm, the challenge of moving toward a circular business model is selecting \"the rationale of how a company creates, delivers, and captures value with and within closed material loops\" [50]. Different business models, such as the product-as-a-service model, the resource recovery and circular supply models, and the product life extension model, all explore pathways toward CE [51]. [PERSON] and [PERSON] [52] determined that there are seven types of barriers that discourage small and medium-sized businesses from implementing CE business models: lack of government support/effective legislation, lack of capital, administrative burdens, deficient corporate culture, lack of technical and technological expertise, lack of network support in supply and demand, and lack of information. Another survey-based analysis of 76 companies indicated that significant initial funding costs, as well as a misunderstanding and sense of urgency, are the main CE adoption barriers at the focal-firm level [53]. Moreover, [PERSON] et al. [54] categorized barriers into those that are internal versus external to the focal firm, and they suggested modes of circular business models that require tailor-made CE solutions.  
At the meso level, the creation of a closed-loop supply chain is crucial for various circular remanufacturing or recycling business models [55]. [PERSON] et al. [56] analyzed CE barriers in a supply chain and discovered that the most common barriers are \"lack of consumer perception towards remanufactured products,\" \"lack of public awareness of CE,\" and \"technology limitation by the enterprises to make products that can be easily remanufactured.\" In addition, [PERSON] et al. [57] analyzed the causal relationships among barriers in a closed-loop supply chain, and their results revealed that the most critical barriers exist in the remanufacturing and sales stages and that the elemental barriers are remanufacturers. Similarly, [PERSON] and [PERSON] [58] recognized the important driving barriers as \"interface designing\" and \"automated synergy model\" in the supply chain context.  
At the macro level, the main actors driving progress toward CE are legislative and governmental bodies. For instance, in China, the Cleaner Production Promotion Law of 2002 and the ensuing Circular Economy Promotion Law of 2009 formally introduced CE into the context of real-world public policy [59]. Moreover, the government of the Netherlands is considered the frontrunner in Europe in pursuing CE [60], and the European Commission has been implementing a variety of ambitious CE policies and launched the circular economy package in 2015, which was updated in the year 2018. In their large-N study on CE barriers in Europe, [PERSON] et al. [61] identified that a lack of consumer interest and awareness and a hesitant organization culture are especially significant CE barriers for business managers and policymakers. [PERSON] et al. [62] aggregated the findings in the literature and developed a CE framework according to \"hard\" and \"soft\" factors. Their results revealed that hard factors (e.g., those that are related to the availability of technical solutions and financing) drive CE, whereas soft factors (e.g., social, regulatory, or institutional) inhibit the implementation of CE.