Monumental Makeover

For the past few years, workers have been slowly giving one of the world’s most famous buildings a much-needed mud bath. When the Taj Mahal was completed 365 years ago in Agra, India, its marble exterior was a brilliant white. But over time, small particles of air pollution around the building turned the stone yellow and black.

To get rid of the grime, workers have been covering sections of the building with highly absorbent clay. As the clay dries, it soaks up the pollutants from the stone. Workers then wash off the dried mud to reveal a restored white surface.

Unfortunately, the monument may not stay clean for long. Despite laws to improve the air quality in Agra, it remains one of the most polluted cities in India. Much of the air pollution comes from vehicle exhaust and the burning of trash to dispose of waste.

“The only way to keep the Taj Mahal clean long-term is to stop the pollution,” says Ajay Nagpure, an environmental scientist at the University of Minnesota.