China's capital Beijing, under fire to take effective measures against air pollution, raised its four-tiered alert system to “orange” for the first time on February 21, 2014. Heavy smog was expected to enshroud the city for an indefinite period.
Pollution in Beijing

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A man wearing a mask makes his way amid thick haze in Beijing, Feb. 25, 2014.

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A man wearing a mask drives a car amid thick haze in the morning in Beijing, Feb. 26, 2014.

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Commuters wearing masks make their way amid thick haze in the morning in Beijing, Feb. 26, 2014.

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Cars drive on the Three Ring Road amid the heavy haze in Beijing, Feb. 26, 2014.