## 3 Literature Review  
### Factors Influencing CO2 Emissions in Cities along the Yangtze River  
Recent academic studies on CO2 emissions in cities along the Yangtze River primarily focus on carbon emissions at the urban level within the Yangtze River Economic Belt (YREB), highlighting a range of determinants and impacts of CO2 emissions. Firstly, on the urban planning and economic dimensions, [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], and [PERSON] [12] and [PERSON], [PERSON], [PERSON], and [PERSON] [14] jointly examined the impact of urban construction land on CO\({}_{2}\) emissions in cities within the YREB. [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], and [PERSON] [12] concentrated on the impact of the scale of construction land, finding that an increase in the scale of construction land by 1% leads to a 0.3101% increase in CO\({}_{2}\) emissions. [PERSON], [PERSON], [PERSON], and [PERSON] [14] further discussed the effects of different categories of construction land, discovering that industrial and commercial lands are the main contributors to the increase in CO\({}_{2}\) emissions, while land associated with support facilities and infrastructure tends to mitigate CO\({}_{2}\) emissions. [PERSON] and [PERSON] [16] initially calculated the carbon emission efficiency of cities in the YREB, then examined the influence of urbanization and foreign direct investment (FDI) on the efficiency of urban carbon emissions. They observed that urbanization leads to increased levels of carbon emissions, while FDI only causes increases in some areas. [PERSON], [PERSON], [PERSON], [PERSON], and [PERSON] [17] analyzed the decoupling of economic growth from CO\({}_{2}\) emissions in cities along the Yangtze River Economic Belt, finding that some cities have achieved decoupling, meaning they have managed to reduce CO\({}_{2}\) emissions while maintaining economic growth. Some studies have considered the factors affecting CO\({}_{2}\) emissions at the urban industrial level. For example, [PERSON] et al. [34] and [PERSON], [PERSON], [PERSON], and [PERSON] [18] discussed the impact of the agglomeration of productive service industries and ICT industries on CO\({}_{2}\) emissions, respectively, confirming that both types of industry agglomeration significantly promote CO\({}_{2}\) emissions. Additionally, some research has focused on the impact of technological development levels. [PERSON], [PERSON], [PERSON], and [PERSON] [13] and [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], and [PERSON] [20] investigated the effects of green innovation and the development of the digital economy on urban carbon emission efficiency, respectively. These studies suggest that green innovation and the development of the digital economy are key drivers in reducing carbon emissions. Policy interventions also play a crucial role, as demonstrated by the research of [PERSON] et al. [35], [PERSON] and [PERSON] [21], and [PERSON] et al. [36], showing that green taxes, regional integration, and urban agglomeration policies have all contributed to the reduction in CO\({}_{2}\) emissions in cities. Some studies have focused on the temporal and spatial variations in urban CO\({}_{2}\) emissions themselves, such as those by [PERSON] et al. [37] and [PERSON] et al. [38]. [PERSON], [PERSON], [PERSON], and [PERSON] [37] found a declining trend in CO\({}_{2}\) emissions in the urban agglomerations of the Yangtze River Economic Belt. [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], and [PERSON] [38] focused on the synergistic relationship between pollution and carbon emissions, finding that the level of synergy between pollution control and carbon reduction in cities along the Yangtze River Economic Belt is on the rise. Lastly, some research has considered a comprehensive range of influencing factors, such as that conducted by [PERSON], [PERSON], and [PERSON] [2], who used the random forest machine learning algorithm to examine the relationship between ten influencing factors and carbon emissions.