(COMBO) This combo shows an image (top) of Beijing's central business district on April 25, 2017 and the same view (bottom) on May 4, 2017 after the Chinese capital was hit by a dust storm. A major dust storm engulfed northern China and Beijing on May 4, prompting authorities to cancel dozens of flights and urge children and the elderly to stay indoors. / AFP PHOTO / Nicolas ASFOURI (Photo credit should read NICOLAS ASFOURI/AFP/Getty Images)
