## 2 Literature Review  
### CE in the Electrical and Electronics Industry  
A generally accepted definition of CE remains elusive, prompting a wide range of ideas and methods being analyzed to devise a concept that can relate circular models to the pillars of sustainability, as proposed by [PERSON] et al. [30]. Some researchers have emphasized the need for new business models that facilitate the transition from open production systems to closed systems focused on product eco-design that reuses resources and reduces energy [12; 31]. Other researchers have affirmed that any circular model must point to three dimensions of impact--environmental, economic, and social [18; 32]. [PERSON] et al. [33] demonstrated that CE can be implemented on the micro-level (i.e., products, companies, consumers), meso-level (i.e., eco-industrial parks), or macro-level (i.e., city, region, nation) to achieve sustainable development to create environmental quality, economic prosperity, and social equity for the benefit of current and future generations.  
As it was pointed out earlier, the European Commission has adopted a new CE Action Plan whose measures consider the entire life cycle of products, as part of a green growth strategy which also gives new rights to consumers. This Action Plan focuses on sectors that are heavy users of resources and have a high potential for circularity. A circular electronics initiative is intended to provide longer product lifetimes, avoid planned obsolescence, and improve the collection and treatment of e-waste [16].  
The CE in the electrical and electronics industry should focus on analyzing the various stakeholders, processes, and scenarios to optimize the use, management, and recovery of resources and materials. This research is based on the CE conceptual framework proposed by [PERSON] et al. [33], [PERSON] et al. [31], and [PERSON] et al. [30], who established that CE is an economic-industrial modeling system that analyzes the inputs and outputs of resources, matter, and energy throughout a product's value chain. This replaces the end-of-life concept with the reuse, recycling, and recovery of secondary raw materials through eco-design, production, consumption, and responsible recycling [34; 35].  
In Mexico, the definition of CE is relatively new, especially in the EEE sector. A study by [PERSON] et al. [12] provided better visibility of Mexico's current situation regarding materialsflow contained in WEEE (e-waste) at the end of their useful lifetimes. The research conducted a material flow mapping from electronic equipment arrival to the consumer and its repair at formal/informal stores or a recycler, where it is disassembled and its materials are recovered. Similarly, in 2017, SEMARNAT and the United Nations Development Program (UNDP) joined forces to devise essential information regarding the WEEE industry's situation and management 2018 [23].  
The integral e-waste management process in Mexico is generated and managed by different actors such as manufacturers, distributors, consumers, repair shops, recyclers, etc. For this reason, electrical and electronic equipment's lifecycle must be determined. Figure 1 describes the general lifecycle of EEE, from its production, sale, and use by the consumer until the last user transforms it into waste [12]. As e-waste, electrical and electronic equipment can be stored by the user, thrown away, or sent to a recycling location. Nevertheless, the appropriate process with the least socio-environmental impact depends on the consumer since they dictate the fate of their obsolete products (for example, repair or go through a diagnosis process, analysis, and evaluation to be reconditioned/remanufactured and re-enter the market). If the operation and conditions of the equipment cannot be recovered, its components and materials are used for repair or to remanufacture other products. To achieve this, a modular eco-design of the parts and components is required for the materials to be recovered; otherwise, they are incinerated or safely disposed of [35; 36; 37; 38].