An online public opinion report said environmental pollution has become the hottest topic among many social problems in China. The 2013 Report of the Online Public Opinion was published by the Internet science research center at Wuhan University.

The report said public attention to the environment has dramatically increased in the first quarter of this year, reflecting a sentiment of "zero tolerance" of environmental pollution.

More environmental incidents occurred in major Chinese cities in the first quarter, including the hazy days in Beijing and Shanghai's dead swine, which became the focus of public attention. However, in the past, environmental incidents that could bring widespread attention were more likely to happen in small cities.

As environmental problems become more serious, the public's sentiments on quality of life and health tend to become more sensitive.