China's energy structure is dominated by coal. Although some progress has been made in desulfurization, denitrification and dust removal in the thermal power industry, which has reduced the emission of air pollutants, the total amount is still huge.Due to low energy utilization rate, insufficient pollution control measures and other factors, small and medium-sized coal-fired boilers emit large amounts of air pollutants, which are an important source of urban air pollution in winter.In order to implement the action plan for prevention and control of air pollution, local governments strengthened the elimination and renovation of coal-fired boilers, and introduced action plans and plans for the treatment of coal-fired boilers to ensure the completion of the 2015 targets.Now select Beijing, tianjin, hebei, henan, shaanxi province and other places for reference.