Could the Construction of Sustainable Development Pilot Zones Improve the Urban Environment Efficiency in China?

Table 1

Assessment index system.

Types	Index name	Index code
Input	Wastewater discharge (10,000 tons)	(I)WW
	Industrial sulfur dioxide emissions (tons)	(I)SO2
	Industrial smoke and dust emissions (tons)	(I)SW
	Unutilized rate of general industrial solid wastes (%)	(I)DUST
Output	Output of the secondary industry (10,000 yuan)	(O)DUSTRY