How has the efficiency of China's green development evolved? An improved non-radial directional distance function measurement

As a key choice for human sustainable development, green development is also one of China's five major vision points. To explore the level of green development in China since it was first written into national documents in 2011, this paper applies an improved non-radial distance function based on Data Envelopment Analysis method to analyze the progress against the development targets set in related national documents. The results show that: (1) China's green development efficiency has kept increasing in 2011-2017. (2) The growth in green development efficiency was signif-icantly higher in the 13th Five-Year Plan period compared to the 12th Five-Year Plan period. (3) The green develop-ment efficiency shows a decreasing trend from south to north, east of the Hu line. This study provides a more practical idea for evaluating the quality of green development in mainland China.