## 3 Methodology  
The methodology employed in this paper primarily relies on a systematic literature review (SLR). SLR plays a pivotal role in defining the scope of the review by synthesizing data and mapping the existing literature in the research area, thereby aiding in the development of frameworks that integrate current knowledge [30; 31]. The SLR process typically involves four main steps, including determining keywords and the inclusion and exclusion criteria, conducting a comprehensive search of relevant publications, filtering these publications based on the established criteria, and finally, discussing and analyzing the finalized set of publications [32]. We collected publications from the Web of Science (WoS) database only since lots of high-quality review papers also collected publications from a single database [33; 34; 35]. We conducted a keyword search on WoS to find the target publications on 22 December 2023. We grouped the keywords into three parts: (1) IoT keywords [25; 36]; (2) the keywords related to \"sustainable\"; and (3) the names of top 100 smartest cities according to the IMD Smart City Index 2023 ([[https://www.imd.org/wp-content/uploads/2023/04/smartcityindex-2023-v7.pdf?trk=public_post_comment-text](https://www.imd.org/wp-content/uploads/2023/04/smartcityindex-2023-v7.pdf?trk=public_post_comment-text)]([https://www.imd.org/wp-content/uploads/2023/04/smartcityindex-2023-v7.pdf?trk=public_post_comment-text](https://www.imd.org/wp-content/uploads/2023/04/smartcityindex-2023-v7.pdf?trk=public_post_comment-text)) accessed on 1 December 2023). Appendix A presents the top 100 smart cities in the IMD Smart City Index 2023 list. Therefore, our final search string is \"TS=(\"internet of thing\"\" OR \"IoT\" OR \"IoTs\" OR \"wireless sensor network\"\" OR \"WSN\" OR \"WSNs\" OR \"Internet of Everything\" OR \"IoE\") AND TS=(sustainable\" OR green\" OR Resilien\" OR environment\" OR social\" OR responsib\" OR eco-friendly) AND TS=(\"Zurich\" OR \"Oslo\" OR \"Canberra\" OR \"Copenhagen\" OR \"Lausanne\" OR \"London\" OR \"Singapore\" OR \"Helsinki\" OR \"Geneva\" OR \"Stockholm\" OR \"Hamburg\" OR \"Beijing\" OR \"Abu Dhabi\" OR \"Prague\" OR \"Amsterdam\" OR \"Seoul\" OR \"Dubai\" OR \"Sydney\" OR \"Hong Kong\" OR \"Munich\" OR \"New York\" OR \"Auckland\" OR \"Wellington\" OR \"Brisbane\" OR \"Shanghai\" OR \"Reykjavik\" OR \"Bilbao\" OR \"Vienna\" OR \"Taipei\" OR \"Riyadh\" OR \"Melbourne\" OR \"Tallin\" OR \"Berlin\" OR \"Boston\" OR \"Brussels\" OR \"Gothenburg\" OR \"Madrid\" OR \"Dusseldorf\" OR \"Washington\" OR \"Ottawa\" OR \"Rotterdam\" OR \"Vancouver\" OR \"Hague\" OR \"Warsaw\" OR \"Luxembourg\" OR \"Paris\" OR \"Ljubljana\" OR \"Toronto\" OR \"Busan\" OR \"Los Angeles\" OR \"Bologna\" OR \"Mecca\" OR \"Denver\" OR \"Zaragoza\" OR \"Seattle\" OR \"Jeddah\" OR \"Hanover\" OR \"Nanjing\" OR \"Doha\" OR \"Zhuhai\" OR \"Chicago\" OR \"Bratislava\" OR \"Dublin\" OR \"Lyon\" OR \"Vilnuis\" OR \"Shenzhen\" OR \"Tianjin\" OR \"San Francisco\" OR \"Montreal\" OR \"Hangzhou\" OR \"Guangzhou\" OR \"Tokyo\" OR \"Manchester\" OR \"Birmingham\" OR \"Barcelona\" OR \"Leeds\" OR \"Newcastle\" OR \"Bordeaux\" OR \"Krakow\" OR \"Glasgow\" OR \"Kiel\" OR \"Milan\" OR \"Riga\" OR \"Lille\" OR \"Medina\" OR \"Chongqing\" OR \"Budapest\" OR \"Bangkok\" OR \"Kuala Lumpur\" OR \"Ankara\" OR \"Tel Aviv\" OR \"Philadelphia\" OR \"Phoenix\" OR \"Cardiff\" OR \"Belfast\" OR \"Muscat\" OR \"Chengdu\" OR \"Osaka\" OR \"Lisbon\" OR \"Hanoi\")\". In addition, we only consider English peer-reviewed studies. Finally, we used the filters in WoS to identify the studies that meet UNSDG 11, \"Sustainable Cities and Communities\", resulting in 255 publications. Then, we screened them and removed the irrelevant articles. The selection process consists of two stages. During the first stage, publications related to the application of IoT in the sustainable development of smart cities are selected through screening of their titles, abstracts, and keywords. We retained 164 publications after the selection in the first stage.