Figure 5
A line graph with two data lines: a red line representing the iso-expenditure line and a green line representing the iso-environmental-benefit line. The horizontal axis is labeled 'Price subsidy coefficient m' and ranges from 0 to 0.9. The vertical axis is labeled 'Green subsidy coefficient τ' and ranges from 0.3 to 2.1. The graph is divided into three regions labeled I, II, and III. In region I, the red line is above the green line, indicating higher green subsidy coefficients for the same price subsidy coefficient. In region II, the lines intersect, showing equal subsidy coefficients. In region III, the green line is above the red line, indicating higher green subsidy coefficients for the same price subsidy coefficient.Policy-space comparison between the price-subsidy and green-subsidy policies based on subsidy expenditure and environmental benefit