This study estimated the shadow price of two air pollutants (sulfur dioxide and nitrogen oxides) and carbon dioxide in 867 chemical firms from 2007 to 2012 using a parameterized directional distance function to measure the marginal abatement cost of pollutants. The result is as follows. 1) The average shadow prices of SO₂, NO_x and CO₂ in the sample chemical firms were 59.8 yuan/kg equivalent, 388.13 yuan/kg equivalent and 164 yuan/ton equivalent, respectively. 2) The shadow prices of the three pollutants showed an upward and fragmented trend, implying that traditional target-bound emission reductions policies during the 11th Five-Year-Plan had not been economically effective. 3) By plotting the marginal abatement cost curve (MACC) of chemical industry, we find that in order to achieve the pollution reduction targets set by the 13th Five-Year Plan, the effective environmental tax rate should be much higher than the current environmental tax rate or the average carbon price in the carbon market, which means that the current environmental tax may require some adjustment. The shadow price of nitrogen oxides is much higher than that of sulfur dioxide, therefore the tax rate of nitrogen oxides may need a certain degree of adjustment. The results can provide some reference for the future establishment of a more complete system of environmental tax.

Based on the data of the Annual Census of Enterprises and relevant socio-economic information, this article empirically investigates the impacts of environmental regulation and path dependence on the distribution of water pollution industries in the Yangtze River basin. The article analyses the path dependence effect through HHI and location entropy. In the empirical model, the two-stage least squares method is used to solve the endogeneity of environmental regulation indicators, which improves the reliability of the conclusions. The results show that the concentration of water pollution industries discharging COD in the Yangtze River is relatively low and dispersed, and the concentration of this industry declines significantly year by year during the period of Eleventh Five-Year Plan. During the period of Tenth Five-Year Plan, the path-dependent effect of water pollution industries discharging COD is significant, while environmental regulation has no significant impact on their distribution. During the period of Eleventh Five-Year Plan, the path dependence no longer has significant impact, and environmental regulation significantly reduces the output and growth rate of the industry. For non-COD water pollution industries and non-water pollution industries, environmental regulation has no significant impact on them. From the perspectives of enterprise ownership types, collective enterprises, private enterprises and foreignfunded enterprises are significantly affected during the Eleventh Five-Year Plan period, while state-owned enterprises and HMT enterprises are not significantly affected. Generally speaking, with the impact of path dependence and environmental regulation on the distribution of water pollution industries shifting from one to another, and with the impact of environmental regulation on the distribution of water pollution industries increasing, continuing to improve environmental regulation polices will contribute to the sustainable development of the Yangtze River basin.

Based on the data of the Annual Census of Enterprises and social-economic data of counties, this article constructs a panel-DID model to investigate the impact of “Two Control Zones” policy on enterprises that discharge water pollution in China. It is found that the “Two Control Zones” policy has a significant impact on water pollution enterprises, resulting in a significant decline in the growth rates of output, newly-built enterprises and the number of existing enterprises in all counties. Moreover, the impact of the “Two Control Zones” policy on enterprises that discharge water pollution is continuous. In the face of the impact of the “Two Control Zones” policy, enterprises that discharge water pollution located in economically developed areas are more affected. When analyzing the initial factors affecting the effect of the policy, it is found that the effect of the “Two Control Zones” policy is more prominent in areas with high education level, high population density, high average wage and large proportion of the secondary industry. Based on the above conclusions, this article holds that the policy of “Two Control Zones” has restrained the aggravation of pollution, and its economic cost is reflected in increasing the burden of water pollution enterprises and slowing down the growth rate of output. However, the magnitude of the increase in social welfare brought about by the reduction of pollution and the slowdown in the growth of enterprise output need to be further assessed.