The smart city is an empowered system constructed using connected, intelligent sensors, smart meters, intelligent cameras, and lights that sense, collect, and analyze the information of the specific environment. Smart cities are also referred to as intelligent cities, cyberville, wired cities, and digital cities. Smart grids, smart infrastructures, automated systems, intelligent transportation systems, smart parking, air quality management, smart waste management are fewer examples of smart city applications.
   A smart city can enhance the quality of human lives and eases daily activities. It maximizes the performance of an environment by sustaining it for a long time. The smart city for IoT consolidates various systems, buildings, and humans to accomplish a specific operation of the working and living environment. The main intention of a smart city is to achieve better connectivity between the physical and virtual worlds. The main pillars of a smart city are social infrastructure, economic infrastructure, physical infrastructure, and institutional infrastructure. Among them, the institutional infrastructure incorporates governance.
   The smart city effectively rectifies the issues of the city by enabling different wireless technologies and operations. Examples of worldwide smart cities are New York, Singapore, Amsterdam, Dubai, London, Hong Kong, Copenhagen, and Barcelona. With IoT, various technologies like artificial intelligence, machine learning models, and blockchain technology are used in smart city construction. Moreover, the IoT-based smart cities observe the current status of future operations prediction and optimize the city functionalities using appropriate methods.