章小玲

导读：印度泰姬陵因污染由白色变为了棕色；研究者们正在采取治污措施。

The Taj Mahal is an important， beautiful structure in India that draws millions of tourists every year. It is well known for its white marble， but lately that marble hasnt been quite white.

For a year， Bergin and other researchers from Georgia Tech and India measured something bad in the air around the palace and its walls to find out what was causing the problem and why it couldnt be washed off by rainwater.

They found that this bad brown thing sticks to the marble， and ultraviolet light from the sun colours them a dirty brown shade. They also found that this bad thing cant be washed off with water.

To clean the building， workers cover its outside walls with a layer of heavy， sticky earth every few years. They leave it on for a while and then take it off， taking away the bad brown thing and bring the Taj Mahal back to its wonderful white.

Bergin and other researchers have set up air testing machines around the Taj to control air pollution levels， but it is up to the people of India， a country with one of the highest levels of air pollution， to do their part to make the air cleaner.

Vocabulary

marble n. 大理石

ultraviolet adj. 紫外線的

（What do you think the Indian government should do？）