This paper conducts a convergence analysis on the energy-environmental efficiency to explore the differences between regions that reflect the implementation effect of the policies on energy-saving and emission reduction. Particularly, for the Yangtze River urban agglomeration, additive model (AM model) is applied to calculate the energy-environmental efficiency, and the convergence model is employed to analyze the heterogeneity and spatial evolution of energy-environmental efficiency. From the results, the energy-environmental efficiency for Suzhou is at a good level; the figures for Wuxi, Yangzhou, and Nantong maintain at medium level; for Zhenjiang, qualified level; and for Nanjing, Changzhou, and Taizhou, poor level. The energy-environmental efficiency of the whole Yangtze River urban agglomeration displays a downward trend of fluctuations. While Nantong reveals a divergent energy-environmental efficiency, Zhenjiang, Changzhou, Wuxi, Yangzhou, and Nanjing Cities generally show a trend of convergence. It was also recognized that the energy-environmental efficiency is gradually decreasing from Southeast to North to Southwest regions. In the past decade, the north region of Yangtze River yielded a divergent development trend, while the southeast and southwest regions appear to have a convergent development trend. In the future, the urban agglomeration needs to promote the coordinated development of the economy and the energy environment, impel the optimization and upgrading of the industrial structure, narrow the regional gap, and adjust the energy consumption habits.
Keywords: Convergence; Energy-environmental efficiency; Environmental constraints; Yangtze River urban agglomeration.