Chinese President Xi Jinping has been checking Beijing's pollution first thing every morning, he told world leaders Monday, after authorities pulled out all the stops to avoid the city's notorious smog during a summit.

The Chinese capital is periodically hit by choking, acrid haze with particulate levels soaring far beyond recommended limits. Public anger is mounting over the issue, tourists are staying away and the Communist government is increasingly embarrassed.

For the Asia-Pacific Economic Cooperation (APEC) meeting Beijing and neighbouring areas have imposed tight limits on car use, ordered factories to close, and given public-sector employees holidays.

The result has been stunning skies popularly dubbed "APEC blue" by online commentators mocking their temporary nature. Even Xi himself used the phrase Monday.

Levels of PM2.5 particulates, the smallest and most dangerous, fell to four micrograms per cubic metre last Thursday -- down from more than 400 during a period of heavy pollution last month. The World Health Organization's recommended maximum is 25.

"These days the first thing I do in the morning is to check the air quality in Beijing, hoping that the smog won't be too bad so that our distinguished guests will be more comfortable while you are here," Xi said at a welcome banquet for leaders and spouses.

"My hope is that everyday we will see a blue sky, green mountains and clear rivers, not just in Beijing, but all across China so that our children will live in an enjoyable environment," he told diners including his US and Russian counterparts Barack Obama and Vladimir Putin.

Xi, the son of a revolutionary hero, is a Communist "princeling" fulfilling a Party destiny to lead the world's most populous country. But his comments are in line with what many believe are efforts carefully to build his image as a man of the people.

Earlier this year, as pollution readings in the routinely smog-hit Beijing hit extreme levels, Xi decided to take a stroll -- without a facemask, but accompanied by television cameras -- in a popular shopping and cafe district.

"Breathing the same air, sharing the same fate," said a widely shared online post.

He described anti-pollution efforts Monday as "a very important part of the Chinese dream", a vague term with connotations of national resurgence which has come to define his lofty aspirations.

"Some people call the clear Beijing sky these days the 'APEC blue', it is beautiful but temporary and it will be gone soon after the APEC meeting," Xi said in a candid admission.

Users of popular mobile messaging app WeChat have defined the colour as "something that is beautiful but fleeting and ultimately inauthentic".