From 2001 to 2005, Chinese environmental authorities received more than 2.53 million letters and 430,000 visits by 597,000 petitioners seeking environmental redress. Meanwhile, the number of mass protests caused by concerns over environmental issues grew steadily from 2001 to 2007. The increased attention on environmental matters caused the Chinese government to display an increased level of concern towards environmental issues. For example, in his 2007 annual address Wen Jiabao, the Premier of the People's Republic of China, made 48 references to "environment," "pollution," and "environmental protection", and stricter environmental regulations were subsequently implemented. Subsidies for some polluting industries were cancelled, while other polluting industries were shut down. However, many internal environmental targets were missed.