06 January, 2015
For years, people living near the Taj Mahal have burned fuel and garbage. Slowly, tiny pieces of those fires are changing the marble on the Taj Mahal from bright white to brownish yellow. The pollution leaves particles that change the marble's color.
The 17th-century monument is located in the busy, industrial city of Agra in northern India. Many have long blamed the city's air pollution for discoloring the famed monument.
Researchers from two American universities and several Indian institutions led a year-long study to test the idea. They placed small pieces of clean marble on the Taj Mahal. They left them there for two months, and then studied the particles that landed on their surfaces.
Professor S.N. Tripathi at the Indian Institute of Technology at Kanpur is one of the authors of the study. He said the particles come from many sources – especially from diesel trucks.
"We have [an] increasing fleet of diesel vehicles nowadays in cities, large vehicles, trucks; that's number one, and that is a major emission source for black carbon and organic carbon."
Mr. Tripathi said burning garbage and cow dung is another major source of discoloring organic carbon. Especially now, when it is cold, he said, people burn almost anything to keep warm.
Efforts to reduce pollution
Over the last ten years officials have banned vehicles within 500 meters of the monument. They have also tried to support clean fuel and improve the power supply to lessen the effect of diesel machines.
But despite these measures, a 2010 study found that the non-stop growth of industry, population and traffic have only worsened air pollution in Agra.
Targeted protection needed
Preservationists, or people trying to keep the monument safe, say the monument needs more targeted protection.
Ratish Nanda in New Delhi said some changes are to be expected in a monument that is over 360 years old. He believes that the single issue of discoloration should not cause an over-reaction.
But Mr. Nanda said the scientific community needs to be more involved in observing and preventing damage to the monument. And, he said the Taj needs more money to protect it.
"The whole preservation mechanism of the Taj Mahal needs to change... Absolutely, the one thing that is absolutely essential is to put in a regime of conservation, that whatever cleaning is done, should be sensitive and have absolutely no long term impact."
Since 1994, authorities have been giving the monument mud pack treatments to remove the discoloration. The treatment is just like the beauty treatment women have used on their faces and bodies for centuries. A mud pack treatment involves covering the Taj's surface with clay, and then taking it off. The monument received the treatment for the fourth time last June, but experts warn the process could have unwanted side effects.
In 2013, nearly 6 million people visited the monument. It is considered one of the finest examples of Mughal art and architecture in India.
I'm Jonathan Evans
Anjana Pasricha reported this story from India. Anne Ball wrote it for Learning English. Kelly Jean Kelly was the editor.
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Words in this Story
particle – n. a very small piece of something
discolor – v. to change in color, especially in a bad way
diesel – n. a vehicle (such as a truck or bus) that has a diesel fuel engine
dung – n. solid waste from an animal
conservation – n. the things that are done to keep works of art or things of historical importance in good condition