Lately, the Ministry of Environmental Protection ("MEP") has enacted and issued the Plan for Ranking Variations to the Urban Environment Air Quality (the "Plan").
The Plan makes it clear that the variation of the urban environment air quality shall be ranked in consideration of an indicator which refers to the variation rate of the integrated air quality index. The Plan sets out the method to calculate such integrated air quality index. That is to use the data collected by all assessment spots within the national environmental air quality monitoring network to work out the ranking periods as well as the respective concentration of all pollutants over the same period of the last year (in particular, such concentration means the average level in 24 hours for sulfur dioxide, nitrogen dioxide, PM10 and PM2.5, the 95th percentile concentration of the average level in 24 hours for carbon monoxide, and, for ozone, the 90th percentile concentration of the average level of those hours when the ozone concentration ranks top 8), and then calculate the individual indicator based on the concentration of each pollutant so as to work out the ranking periods for all cities and the integrated air quality index during the same period of the last year. Moreover, the Plan provides that it is required to announce the top 10 cities in which the air quality improves or deteriorates to a relatively large extent, in addition to the best 10 cities and the worst 10 cities with regard to the air quality.