BEIJING, July 14 -- "A promise weighs more than a thousand pieces of gold." One of the most treasured traditional virtues of China is to keep a promise.

That explains why Beijing Mayor Wang Anshun told the International Olympic Committee (IOC) members in June's candidate city presentation in Lausanne that Beijing is a "safe choice" for the 2022 Winter Games host city.

Back to 2008, Beijing had duly delivered its promises of staging an Olympics Games that saw unimpeded flow of traffic, improved air quality, sufficient accommodation as well as dozens of up-to-date stadiums.

To ease the traffic jams, Beijing then imposed a vehicle restriction, which limited cars to every other day on the road based on odd and even license plate numbers. In the meantime, one lane of many key roads were designated as an Olympics lane.

In an effort to tackle air pollution, Beijing upgraded its coal-fired heating system in urban area to natural gas heating system and closed down heavy-polluted plants. Neighboring city Tianjin and provinces including Hebei adopted similar measures to give Beijing a hand.

As Beijing is seeking to become the first city to host both Summer and Winter Olympics, the legacies from the 2008 Games, including the showpiece venues "Bird's Nest" and the "Water Cube" as well as the Games operation experiences, will help the Chinese capital honor its promise once again.

Just take the air pollution issue for example. Compared to the city in 2008, Beijing's population rose from 16.9 million to 21.5 million and the number of vehicles increased by two million. Thanks to continued efforts to improve the air quality, however, Beijing registered fewer air pollutants and more clear days in the first six months in 2015.

Concentration of PM2.5, airborne particles measuring less than 2.5 microns, which are small enough to enter the bloodstream, dropped to 77.7 micrograms per cubic meter, down 15.2 percent year on year.

"China is going all out to bring 'Olympic Blue' to Beijing," said Mayor Wang.

"We are the safest choice for the IOC, the most reliable partner for all stakeholders, and we are confident of that."