An empirical study on industrial ecological efficiency in arid 1 resource exploitation region of northwest China 2

1 11 Located in the northwest of China, Xinjiang is a typical arid desert area and mineral resources 12 development zone. Lacking water resources and a fragile ecological environment restricts the 13 sustainable development of the region. Based on the industrial panel data of Xinjiang from 2001 to 14 2015, this paper uses the Undesirable Output SBM model, Malmquist index model, and Tobit 15 regression model to comprehensively and systematically measure and evaluate the industrial eco- 16 efficiency and its change characteristics from provincial, regional and prefectural levels. The results 17 show that:(1) The level of industrial eco-efficiency in Xinjiang is generally low, lower than the 18 national average, but it has been rising steadily over time, from 0.36 in 2001 to 1.00 in 2008, and 19 from 0.41 in the "Tenth Five-Year Plan" period to 0.99 in the "Twelfth Five-Year Plan" period. (2) 20 The industrial ecological efficiency of Xinjiang is not balanced in space. Northern Xinjiang is larger 21 than that of eastern Xinjiang and southern Xinjiang. The 14 prefectures have uneven and 22 asynchronous development, which can be divided into two development modes: industrial region 23 and agriculture and animal husbandry region. (3) Through the decomposition analysis of the 24 Malmquist index, it is found that the technology progress index is the restriction factor of the 25 changing trend of TFP, while the technical efficiency index and the pure technical efficiency index 26 are the promoting factors. (4) The main factors causing the loss of ecological efficiency are 27 industrial sulfur dioxide emissions, industrial nitrogen oxide emissions, total industrial water 28 consumption, general industrial solid waste. It can be seen that the emission of air pollutants and 29 excessive industrial water are the main problems in the region. (5) Industrial ecological efficiency 30 is positively correlated with industrial development level, scientific and technological innovation, 31 industrial structure, and environmental planning, and negatively correlated with opening up and 32 industrial agglomeration degree. (6) Xinjiang is an extremely arid and water-scarce region. These 33 are the key and prerequisite of saving water resources and strengthening the comprehensive 34 utilization of water resources. Water- saving should be given top priority no matter in industrial 35 areas, or agricultural and animal husbandry areas. 36

indexes, namely, energy consumption, electricity consumption, and water resource consumption, 143 were selected as input indexes; three types of environmental pollution indexes, namely, exhaust gas 144 discharge, wastewater discharge, and solid waste discharge, were selected as Undesirable Output 145 indexes; and economic value was selected as expected output indexes. The evaluation index system 146 of industrial ecological efficiency is constructed (See Table 1

Results and analysis
168 The SBM-Undesirable model is adopted, and DEAP2.1 software and DEA-Solver Pro software 169 are used to measure and analyze the industrial eco-efficiency of Xinjiang from 2001 to 2015, from 170 the static and dynamic aspects, as well as from the provincial, regional and prefectural levels, to 171 find out the temporal and spatial variation rule. The results are as follows. 172 indicating that northern Xinjiang is greater than that of eastern Xinjiang and southern Xinjiang. 213 a "W" shape with a rising rate of 12.00%. The industrial ecological efficiency in southern Xinjiang 217 fluctuated frequently, with a slight increase of 20.73% in the end. From the "10th five-year plan " 218 to "11th five-year plan" to "12th five-year" period, the ecological efficiency value changes from 219 0.4066 0.8207 0.9889

Static ecological efficiency measurement and analysis
to the 12th five-year" period, the industrial ecological efficiency showed a trend of stage rise.

Spatial distribution analysis 276
To further analyze the composition and causes of the Malmquist index changes in Xinjiang, 277 Malmquist indexes of 14 Prefectures in Xinjiang were decomposed and analyzed, as shown in Table  278 3. 279 with a decline rate of 3.3%. In particular, the technology progress index in Kashi prefecture declined 292 by 10.3%. It can be seen that the technical progress index is the leading factor for the decline of 293 total factor productivity，It has a restrictive effect on total factor productivity. But the technical 294 efficiency and pure technical efficiency index play a promoting role. 295 (3) On the whole, TFP shows a downward trend, in which technical efficiency plays a promoting 296 role and technological progress plays a restricting role, while scale efficiency has little influence. In 297 Urumqi, Karamay, Turfan, Changji, and most of the other prefectures, Technological efficiency is 298 the main factor that promotes TFP, while technological progress is the constraint. In Altay and Hotan, 299 both technological progress and technical efficiency play a promoting role, while in Bazhou, 300 technological progress plays a promoting role and technical efficiency plays a restricting role. 301

Input-output redundancy results 305
In this paper, the input redundancy rate is obtained by dividing the slack of each input variable by 306 the corresponding input index value, and the output redundancy rate is obtained by dividing the 307 slack of each output variable by the corresponding output index value. The calculation results are 308 shown in Table 4.   The following conclusions can be drawn from Table 4  for industrial input elements. The redundancy rate of Urumqi is less than the mean value, and the 354 problem of the excessive input-output index is not too prominent. Excess industrial water is a 355 common problem in all prefectures except Urumqi. We need to take measures to address problems

Analysis of improvement approaches
throughout the country, having been included in the national environmental pollution battle-"battle 386 to protect the blue sky". At present, the air quality of the whole of China is not optimistic, especially 387 in the northern cities. About 70% of the prefectures in Xinjiang fail to meet the air quality standards. 388 Therefore, the task of controlling the emission of air pollutants is arduous and urgent. Xinjiang is a 389 resource-developing province. Its industries are mainly coal mining, metal mining, limestone 390 mining, and mineral processing, and the amount of industrial waste gas is relatively large. It is a 391 problem to be solved in the future how to improve the quality and efficiency of the existing resource-392 based enterprises and reduce the emission of waste gas pollutants. 393 (2) Industrial wastewater emission. As can be seen from Fig15 and 16, Hami, Changji, Aksu, 394 Yili, and Bozhou all have the problem of excessive redundancy rate of COD discharge in industrial 395 wastewater. It is related to local imperfect sewage treatment facilities and the low comprehensive 396 utilization rate of sewage, which is the direction of further adjustment and improvement in these 397 areas in the future. 398 (3) Industrial solid waste production. As can be seen from Fig 17, Hami City, Changji Prefecture, 399 Aksu, Yili, and Tacheng have the problem of excessive redundancy rate of industrial solid waste 400 production. A large amount of industrial solid waste is mainly produced in mineral mining and 401 processing enterprises, and the production of tailings, waste rock, and the waste residue is relatively 402 large. In the future, it is necessary to improve the mining rate, recovery rate, and comprehensive 403 utilization rate of solid waste. + PGDP +ln FIr + EIr +ln RDr +ln HIr + IGr + ER =α β ( ) β ( )β ( ) β ( ) β ( )β ( )μ

4.2
The common problem in arid areas is water shortage and the ecological problems caused 501 by water shortage. Through the analysis of input-output redundancy, it can be seen that the 502 redundancy rate of industrial water input in 7 of the 8 inefficient regions is all excessive, which 503 indicates that industrial water excess is a common problem in the industrial development of Xinjiang. 504 Turpan is a city with extreme drought and water shortage. Due to the remarkable effect of water-505 saving and water recycling measures, the industrial ecological efficiency level is high, reaching the 506 effective ecological frontier. The water resource is a limiting factor for the development of arid areas. 507 Saving water resources and improving the comprehensive utilization efficiency of water resources 508 is the key to improving ecological efficiency. How to improve the distribution and utilization of 509 water resources and improve the recycling level of water resources is urgent.  improve the level of industrial development. We will mainly implement measures to raise workers' 547 income and increase industrial output; Second, introduce new technology and further improve the 548 level of industrial technology research and development and promotion efforts; Third, strengthen 549 environmental planning and environmental protection management, actively guide enterprises to 550 strengthen the prevention and control of industrial pollution, improve the level of clean production, 551 and implement energy-saving, consumption reduction, and emission reduction; Fourth, we should 552 be cautious in introducing foreign investment, do a good job in the preliminary environmental 553 planning demonstration, and resolutely resist unreasonable demands and additional conditions that 554 are not conducive to environmental protection. 555 4.6 This study has rich levels, continuous data, comprehensive data, and longtime span, which 556 has important guidance and reference for the study of arid resource areas. In this study, ecological 557 efficiency was measured and analyzed from the provincial level, regional level, and prefectural level. 558 The changing trend of industrial eco-efficiency in Xinjiang is demonstrated from the "Tenth Five