Balanced panel data

Due to the availability and reliability of data, this study uses balanced panel data of 108 prefecture-level cities in the Yangtze River Economic Belt from 2008 to 2021 (taking into account data availability, excluding Tongren City and Bijie City that changed administrative levels in 2011 ), including a total of 1596 sample observations. These data sources include publications such as the "China Statistical Yearbook", "China City Statistical Yearbook", "China Environmental Statistical Yearbook", "China Science and Technology Statistical Yearbook" and statistical yearbooks of various provinces and cities. In terms of handling missing values, the linear interpolation method has been applied, ensuring that data from each province are processed and distributed proportionally for consistency.