A Chinese Government report has shown that the air quality in Zhangjiakou, a main venue hub for the Beijing 2022 Winter Olympics and Paralympics, has improved since 2017.
The city, located 200 kilometres north-west of Beijing in Hebei province, will host snowboarding, freestyle skiing, cross-country skiing, ski jumping, Nordic combined and biathlon competitions at the 2022 Winter Games.
The Ecological Environment Bureau of Hebei has ranked Zhangjiakou as first in the province in terms of air quality, as reported by Xinhua.
According to the report, Zhangjiakou's reading reached 4.11 on the air quality index in 2018, down by 0.07 year-on-year.
The average concentration of particulate matter was 29 micrograms per cubic metre, two micrograms less than in 2017.
Zhangjiakou has been rated the city with the best air quality in the region for five consecutive years.
A series of measures have been implemented recently to improve the environment in Zhangjiakou.
The city is set to become Beijing's water conservation area and "ecological environment supporting area", with 400,000 hectares of trees planted in Zhangjiakou last year.
Last year also saw 105 mines closed and 4,518 new energy buses launched.
All venues for the Games will be powered by green electricity, following the signing of an agreement between the Organising Committee and the State Grid Corporation of China last week.
Air quality and pollution were major concerns surrounding the Beijing 2008 Summer Olympics.