## 2 Literature Review
### Internet of Things and the Sustainable Development of the Smart City  
A smart city is defined as \"an urban environment that utilizes information and communication technology and other related technologies to enhance performance efficiency of regular city operations and quality of services provided to urban citizens\" ([6], p. 697). Smart cities can promote sustainable development through various smart solutions, such as smart grids, smart factories, smart warehouses, smart communities, smart healthcare, smart transportation, and smart hospitals [6]. For instance, the implementation of a smart grid in Helsinki resulted in a 15% reduction in energy consumption [22]. Smart healthcare systems can record cases and monitor epidemic trends, as demonstrated during the COVID-19 pandemic [13]. Additionally, smart mobility services like Jelbi in Berlin, which integrate various transportation options, aim to foster a transition towards more sustainable mobility [13]. The sustainable development of smart cities encompasses most of the UNSDGs and ultimately contributes to achieving SDG 11, \"Sustainable Cities and Communities\" [9; 13]. The IoT plays a vital role in the realization of these smart solutions. The IoT is the main component in many smart cities, such as Singapore, London, and Helsinki [10]. By monitoring parameters like energy consumption, water quality, and traffic flow through IoT, smart cities can proactively anticipate risks and implement preventive measures, thereby enhancing sustainability [21]. The IoT connects billions of sensor devices to the Internet, offering advantages such as cost-effectiveness, ease of use, and real-time information retrieval [5]. Consequently, the IoT is widely used in environmental management, allowing the detection and evaluation of changes in pressure, gas levels, and temperature, among other factors [5]. For example, London installed 100 IoT sensors in 2019 to monitor air quality [10]. In 2017, the University of Helsinki monitored air quality with an IoT system [10]. Furthermore, the data collected through IoT facilitates the efficient distribution of energy and public resources. For instance, Singapore utilizes IoT technology to manage solid waste through an integrated waste management facility, improving treatment efficiency and reducing greenhouse gas emissions [23]. Furthermore, IoT greatly increases the potential for disaster detection and disaster risk analysis, enabling rapid response to disasters [24]. Many practical examples show that the IoT is effective in monitoring natural disasters, sending warnings, and alerting disaster management authorities [24]. In 2020, 23 UN countries had efficient disaster early warning systems, which protected 93.63% of the population at risk of natural disasters in these countries successfully [25]. Therefore, the IoT can help smart cities improve environmental sustainability. In addition, IoT can also help smart cities improve social sustainability. The IoT helps create a society that citizens trust [10]. Centrist citizen orientation is a common feature of the IoT systems in Singapore, London, and Helsinki [10]. If citizens can access information transparently from the city's website and information panel, they will develop trust and engagement in the city [10]. Furthermore, the IoT also can improve the security of smart cities. For example, Singapore, which installed sensor cameras on its streets to identify facial features, reported no thefts or robberies in 322 days in 2018 [10]. What is more, IoT-supported smart healthcare can help hospitals monitor patients' physiological parameters for early detection of clinical deterioration [26]. Additionally, IoT technology has the potential to communicate instant information updates and can become a key player in disaster relief activities [27]. The dynamic nature of the requirements and environment in rescue operations emphasizes the ability to make effective and precise decisions in the shortest possible time [27].