Key facts on Xi'an environment in 2013     Updated: 2019-01-31

Air quality

9 days in Grade I*, 2% of days in the year.

129 days in Grade II, 36% of days in the year.

106 days in Grade III, 29% of days in the year.

54 days in Grade IV, 15% of days in the year.

33 days in Grade V, 9% of days in the year.

34 days in Grade VI, 9% of days in the year.

*According to the criteria of the National Environment Air Quality Standard (GB 3095-2012), the air quality is divided into six grades, in which the air pollution index is arranged in ascending order.

Water quality

Of the 13 rivers running through or around the municipality, 7 have been contaminated more severely while 6 are becoming better. The overall pollution index dropped by 10.0% compared to the previous year.

Outdoor noise

The environmental noise maintained a stable level in 2013, except a few areas were increasingly affected by construction noise. According to the international criteria, all 5 functioning areas met the daytime noise standard, while 2 passed the night-time noise standard.