National Geographic : 2015 Aug
Us EXPLORE PHOTOS: STEVE MCCURRY (TOP); MIKE BERGIN Once a shining vision in white, the world-famous Taj Mahal has lost some luster over the past few decades. As the population of the surrounding city of Agra, India, swelled and air pollution worsened, the marble of the 17th-century monumental tomb began to turn brownish yellow. No one knew the exact cause of the discoloration, though. Was it manufac- turing? Transportation? Construction? Or some other activity in the burgeoning industrial hub? Now a study carried out by scientists from the United States and India has identified the culprits: dust, likely stirred up by the traffic on unpaved roads; and soot produced by burning trash, agricultural ref- use, fossil fuels, and the dung and wood that locals use in fires for cooking and warmth. The official response was swift. “Our paper came out, and within two weeks it was being discussed in the Indian Parliament,” says environ- mental engineer Mike Bergin. Authorities in Agra then adopted plans to improve air quality, which include giving people propane to cook with and switching several thou- sand trucks from diesel to natural gas. —A. R. Williams Rescuing an Icon In 1983, when the photo above was taken, the Taj Mahal’s marble was dazzling. Since then, polluted air has covered the stone with dark particles that even the monsoon rains can’t wash off. To restore the original color, a mud pack is applied periodi- cally, followed by a distilled water rinse. A cleaning in progress is shown at right, be- hind the workers’ scaffolding.