The southwest China's Tibet Autonomous Region had "excellent" or "good" air quality on about 97.5 percent of days in 2017, according to a report on the region's environment.

The figure also represented an increase of 7.5 percentage points over 2016, according to the report.

To improve air quality, Tibet shut down six cement plants, eliminated more than 5,100 old vehicles and 157 coal-burning boilers last year. The region also carried out more than 1,600 special inspections on air pollution caused by construction dust.

Tibet will eliminate more old vehicles and control construction dust this year to improve air quality.