[Analysis of Change and Driving Factors of River Environmental Quality in China from 2002 to 2020].

According to the river environmental quality, pollutant emission, and investment in environmental pollution control from 2002-2020, the change law and driving factors of river environmental quality in China were evaluated using canonical correlation analysis and the Spearman correlation coefficient to analyze the influence between environmental and pollutant emission/investment in environmental pollution control. The results indicated that the river environmental quality was improved significantly based on the proportion of Class Ⅰ-Ⅲ increasing from 29.1% to 87.4% and the proportion of inferior Class Ⅴ decreasing from 40.9% to 0.2% from 2002-2020. The emission of wastewater and domestic wastewater increased from 4.395×10 ¹⁰ tons and 2.323×10 ¹⁰ tons to 8.491×10 ¹⁰ tons and 6.598×10 ¹⁰ tons, respectively. However, emissions of industrial wastewater decreased from 2.072×10 ¹⁰ tons to 1.680×10 ¹⁰ tons. Investment in environmental pollution control increased from 110.66 billion yuan to 1063.89 billion yuan. The proportion of Class Ⅰ-Ⅲ in seven major river basins, river basins in Zhejiang and Fujian, southwest river basins, and northwest river basins showed a negative correlation for industrial pollutant emissions and a positive correlation for investment in environmental pollution control. The primary measure for the seven major river basins, river basins in Zhejiang and Fujian, and northwest river basins cut down the industrial pollutant emissions, in the order of COD>NH ₄ ⁺ -N>total wastewater. The primary measure for southwest river basins increased the investment in environmental pollution control, in the order of industrial investment in environmental pollution control>urban environmental infrastructure construction investment and environmental protection investment in construction projects. These results can provide theoretical and policy suggestions for the improvement of river environmental quality during the "14 ^th Five-Year Plan" period.