Before and after: What a difference a day makes for Beijing’s smog

Heavy pollution shrouded Beijing until a strong north wind arrived late Tuesday, helping to clear the sky. China's capital and many cities in the northern part of the country recorded the worst smog of the year on Nov. 30 and Dec. 1, with air quality devices in some areas unable to read such high levels of pollutants.

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Forbidden City

(Kevin Frayer / Getty Images)

Forbidden City

(Kevin Frayer / Getty Images)

Tiananmen Square

(Kevin Frayer / Getty Images)

Tiananmen Square and the Great Hall of the People

(Kevin Frayer / Getty Images)

Tiananmen Square, Monument to the People's Heroes and Memorial Hall of Chairman Mao

(Kevin Frayer / Getty Images)