## 1 Introduction  
Cities are the hubs of economic, social, cultural, and everyday life [1]. Currently, the urban population is 4.27 billion, making up approximately 55% of the global population [1, 2]. Projections indicate that by 2050, around 70% of the world's population will reside in cities, significantly expanding urban areas by 1.2 million km\({}^{2}\)[2]. Despite being centers of activity, cities often grapple with higher population densities, posing challenges in providing adequate services and infrastructure for their residents [3]. Rapid urbanization and industrialization have hindered sustainable development, leading to issues such as pandemics, severe environmental pollution, inefficient waste management, strained power grids, traffic congestion, and the uneven distribution of education and medical resources [4]. For instance, cities currently account for 60% of energy consumption and over 75% of greenhouse gas emissions globally [5]. Smart cities present a promising solution to tackle these challenges, including epidemic control, population growth, environmental pollution, and energy shortages [6]. For example, [PERSON] and [PERSON] [7] found that COVID-19 would be more controllable in smart cities. Generally speaking, a smart city is defined as \"an urban environment that utilizes information and communication technology (ICT) and other related technologies to enhance performance efficiency of regular city operations and quality of services provided to urban citizens\" ([6], p. 697). A crucial component of smart cities is the Internet of Things (IoT), an infrastructure enabling devices to communicate over the Internet [3]. The IoT provides critical components for smart cities, such as data collection, data analysis, and application handling [6]. Byharnessing IoT capabilities, smart cities can gather and analyze data on climate, emissions, traffic, waste management, and disasters [8]. Utilizing these data, smart cities can develop various applications to improve transportation, urban infrastructure, resource utilization, urban life, governance, and the overall environment [9]. Consequently, the IoT contributes to the sustainable development of smart cities and enhances the quality of life for their citizens [10]. Effectively integrating IoT technology into the construction of smart cities is a critical aspect of building a developed and sustainable society [10]. Thus, IoT plays a pivotal role in helping smart cities achieve the United Nations' Sustainable Development Goal (UNSDG) 11, \"Sustainable Cities and Communities\" [9]. Lots of practical examples show that the IoT is able to improve the sustainable development of smart cities. With IoT technology, Santander City and Nice City can use sensors to collect data on available parking lots to implement smart parking management systems [11; 12]. The IoT-based smart lighting system in Padova city can monitor lighting periodically or upon request based on the light intensity data collected from sensors, which saves energy, reduces maintenance costs, and improves service quality [6]. The literature has shown a substantial research interest in the application of IoT in smart cities, leading to several existing reviews, such as those by [PERSON] et al. [13], [PERSON] et al. [1], [PERSON] et al. [14], and [PERSON] et al. [6]. However, there remains a scarcity of comprehensive understanding regarding the role of IoT in fostering sustainable development within smart cities. Therefore, this study aims to contribute valuable insights into the utilization of IoT in the context of smart cities, with a particular focus on its implications for sustainable urban development and bridging the knowledge gap. Therefore, we develop the following research questions:  
1. What types of sensors are used to collect data? What are the different aspects of smart city sustainability?