Air Pollution and Smog Return to Beijing's Perfect 'Parade Blue' Skies

China is known for its smoggy, black skies that can cause health hazards to the public. But for a few days before Beijing's military parade, the city experienced perfect, azure skies.

In the two-week run-up to the celebration to mark the 70^th anniversary of Japan's defeat in World War II, Beijing's notoriously polluted skies were suddenly clear. Then, less than 24 hours later, a blanket of smog once again covered the city.

So what caused the clear and blue skies? Apparently, the government imposed a ban on driving cars, asking the 5 million cars in the city to drive every alternate day. In addition, the government suspended the operations of 12,255 coal-burning boilers, factories and cement-mixing stations in preparation for the parade.

On the day of the parade, the city's air quality index measured 17 out of 500. The day after the parade, though, it hit 160 in parts of the city, a level at which everyone may begin to experience some adverse health effects, according to the LA Times.

"It was as good as the annual index in some metropolises in developed countries, such as Paris, London, Moscow and Singapore," said Zhang Dawei, head of the Beijing Municipal Environmental Monitoring Center, in an interview.

It seems that now, though, Beijing's skies have returned to their normal grey rather than the perfect, blue skies seen on parade day.

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