# Practical Approach for Smart and Circular Cities: Chatbots Used in Waste Recycling
## 1 Introduction  
In 2050, approximately 70% of the world's population is estimated to live in the urban environment [1], so the urban agglomerations formed will need an intelligent infrastructure that can optimally manage the needs of citizens and offer increasingly diverse and more efficient services [2].  
In this sense, the concept of the circular economy (CE), in which resources must be used for as long as possible and saved, has attracted special attention in recent years to achieve sustainable (urban) development. In this context, the digital CE represents a new approach through which digital technologies can enable the development of a more circular and regenerative global economy. Within the framework of the CE, the generation of waste is systematically curtailed through meticulous product design and an industrial process characterized by the perpetual circulation of materials within a \"closed-loop system\". This paradigm prioritizes sustainability by minimizing the linear progression from resource extraction to disposal, promoting a regenerative and resource-efficient approach to production and consumption [3].  
Furthermore, in this context, the implementation of waste management and recycling is of paramount importance in the dynamic landscape of smart cities, where the intersection of urbanization and advanced technologies requires a sophisticated approach to environmental management. As urban centers face increasing volumes of waste, the need for sustainable waste practices becomes key to the ecological resilience of smart cities [4]. Moreover, the ubiquity of waste has reached a global scale, with an unprecedented demand for raw materials. Statistics indicate that approximately 80% of all materials and consumer goods are subject to disposal, contributing to an increasing challenge. Furthermore, within the intricate web of the food supply chain, an alarming excess of more than 30% of processed food is discarded, underscoring the urgent need for comprehensive waste management strategies [5].  
The hypothesis of our research posits that AI-driven IT applications play a pivotal role in smart-city contexts, particularly in addressing waste management challenges. Therefore, the incorporation of AI technologies emerges as a strategic imperative to optimize waste processes, promote resource efficiency, and ultimately contribute to the overall goal of sustainable urban development [6].  
Building on our previous research endeavors, which resulted in the publication of scientific articles on this topic [7; 8], the present research study aims to examine five illustrative examples of chatbots employed in the field of waste management, with a specific focus on material recycling. In addition to our previous work, we posit certain directives and methodologies capable of enhancing the efficacy of software implementations of this nature.  
In the concluding section of this article, we derive comprehensive insights, underscoring the pivotal role of chatbots in the circular economy. Additionally, we describe their practical implementation, culminating in a set of conclusions that highlight the importance of these intelligent systems in fostering sustainable practices and circular economy initiatives.