This paper proposes a Malmquist energy conservation and emission reduction performance index (MECERPI) for assessing the performance changes in energy use and pollutant emissions over time. The index is built upon the non-radial directional distance function and can be derived by solving data envelopment analysis. We apply the MECERPI to empirically investigate the industrial performance of energy conservation and emission reduction in over two hundred cities in China as well as its influential factors. Our empirical results show that due to the combined effects of technological progress and efficiency improvement, the energy conservation and emission reduction performance of Chinese industry has improved at an average annual rate of 16%. The catch-up effect and convergence exist throughout the country, including the eastern, central, western and northeastern regions. The best performers, which act as the benchmark for industrial energy conservation and emission reduction, are the coastal cities in eastern China. (C) 2015 Elsevier Ltd. All rights reserved.