Industrial SO2 technical efficiency, reduction potential and technology heterogeneities of China's prefecture-level cities: A multi-hierarchy meta-frontier parametric approach

Excessive emission of industrial SO2 has seriously restricted the sustainable development in China. Therefore, in this paper, considering the heterogeneities of resources endowments, and regional development levels, a multi-hierarchy meta-frontier parametric approach was proposed to evaluate the industrial SO2 technical efficiency (STE) of China's cities from the year of 2003 to 2016, which was further divided into structural, technical and management efficiency. Moreover, the statistical noises in linear programming parameters were taken into ac-count by following the bootstrap approach. Furthermore, the "resource curse" and "regional development imbalance" in China were discussed, and the industrial SO2 reduction potential was estimated according to the sources of inefficiency. The conclusions are drawn as follows: (1) The STE values in most of the cities of China have greatly improved and the cities with efficiency improved more than twice were mainly located in central and western China. Meanwhile, the average STE in the mainland China showed an upward trend, from 0.43 in 2003 to 0.81 in 2016. (2) The average STE and structural efficiency in non-resource cities were greater than those of resource-based cities, which reflected significant production technology heterogeneity between both types of cities. (3) Irrespective of both types of cities, the industrial production technology showed distinct spatial gradient characteristics. Meanwhile, due to the relatively high management efficiency, the industrial input of resources in eastern cities could be more rationally allocated. (4) By optimizing industrial structure, narrowing the technical gaps, and promoting market-oriented reforms and strengthening environmental regulations, China's industry SO2 emissions could have been reduced by about 1800 kt. And the specific SO2 emissions reduction strategies and pathways for the non-resource and resource-based cities were proposed according to the causes of inefficiency.