Table 2 Explanation and description of variables.
Driving factor | Variable declaration | Symbol |
|---|---|---|
Economic development level | GDP per capita is used to measure this indicator | X1 |
Industrial structure | Referring to the method of Gan et al.30, the ratio of value-added of tertiary industry to gross regional product is used to measure the industrial structure | X2 |
Green technology innovation | According to the approach of Song et al.31, the innovation level of green technology is measured by the number of 10,000 green patent applications | X3 |
Green finance | Referring to the study of Liu and He32, an evaluation index system is constructed to measure the green finance index of each city | X4 |
Environmental regulation | The ratio of pollution control investment to industrial added value was used to measure environmental regulation | X5 |
Level of digital economy | According to the practice of Zhao et al.33, the evaluation index of digital economy is constructed, and the level of digital economy of urban agglomerations in the central area of Yangtze River Delta is measured by entropy method. | X6 |
Urbanization level | The ratio of the non-agricultural population to the resident population at the end of the year was used to measure the urbanization level | X7 |
Spatial proximity | If two cities are adjacent, take 1, otherwise take 0 | X8 |
