Smart Cities: A Systematic Review of Emerging Technologies

In the 21st century, rapid urbanisation has brought both challenges and opportunities. Smart cities have emerged as innovative solutions to meet the complex demands of urban life. Information and Communication Technology (ICT) serves as the backbone of this transformation, integrating infrastructure, public services, and environmental sustainability. Within ICT, the computing continuum has become a key paradigm for efficient resource management, while Artificial Intelligence (AI) and the Internet of Things (IoT) enhance urban planning, optimise resource use, and strengthen governance. This paper systematically reviews smart city developments from January 2020 to June 2025, focusing on technological advances and sustainability goals in databases such as Scopus, IEEE Xplore, and Web of Science. By synthesising the literature, it identifies common challenges, implementation strategies, and future directions. The review highlights the central role of the computing continuum and AI, covering enabling technologies, applications, case studies, and deployment challenges. Our findings indicate that the IoT, AI, and data analytics are currently dominant approaches, yet significant gaps remain in citizen participation, equitable access, and long-term governance. Overall, smart cities aim to integrate data, digital technologies, and intelligent infrastructure to improve the quality of life while promoting sustainable, resilient, and inclusive services.