BEIJING, May 16 (Xinhua) -- Beijing saw better air quality and more "good air" days in 2017, while the city's water quality also improved, according to a report relased by the Beijing Municipal Environmental Protection Bureau on Wednesday.

Average density of PM2.5 in Beijing stayed at 58 micrograms per cubic meter of air in 2017, down by 20.5 percent compared with the average level in 2016, and a decrease of 35.6 percent compared with 2013, the report said.

The city has met the goal set by the State Council in 2013, the report said.

Density of three major pollutants -- sulfur dioxide, nitrogen dioxide and PM10 -- also dropped sharply to 8, 46 and 84 micrograms per cubic meter of air, down 20 percent, 4.2 percent and 8.7 percent, respectively, compared with 2016.

The capital saw 226 good air days in 2017, 28 days more than in 2016. The number of heavy pollution days decreased by 16 to 23, according to the report.

Water quality has also improved. The density of ammonia nitrogen dropped to 2.62 milligram per liter of water, down 51.5 percent compared with the previous year, the report said.

A total of 92 percent of the city's wastewater was treated last year, according to the report. The city used more than one billion cubic meters of recycled water last year, 26.6 percent of the city's total water consumption.