SHANGHAI, Jan. 9 (Xinhua) -- Local authorities said on Monday that the average PM2.5 density in Shanghai was 45 micrograms per cubic meter in 2016, down by 15.1 percent from 2015 and 27.4 percent from 2013.
According to Shanghai Environmental Protection Bureau, the average density of sulfur dioxide, PM10 and nitrogen dioxide in 2016 reported a year-on-year decrease of 11.8, 14.5 and 6.5 percent, respectively.
The number of days with air quality rated "good" or "excellent" accounted for 75.4 percent of the year in 2016, 4.7 percentage points higher than in 2015.
PM2.5 was found to be the primary pollutant in Shanghai last year, accounting for 49 percent of the pollutants monitored during days with air quality rated "polluted."
In order to improve air quality, Shanghai upgraded nine coal-fired units to reduce emissions and removed 53,000 highly-polluting vehicles during 2016.