When the International Olympic Committee met seven years ago to choose a host for the 2022 Winter Games, China’s leader, Xi Jinping, sent a short video message that helped tip the scale in a close, controversial vote.

China had limited experience with winter sports. Little snow falls in the distant hills where outdoor events would take place. Pollution was so dense at times that it was known as the "Airpocalypse.”

Xi pledged to resolve all of this, putting his personal prestige on what seemed then like an audacious bid. "We will deliver every promise we made,” he told the Olympic delegates meeting in Malaysia’s capital, Kuala Lumpur.