UNESCO is urging governments of the world to better balance tourism with protection, fearful that some of most beautiful and important cultural and natural sites are being harmed by throngs of visitors.
"Tourism can be a benefit as well as a threat," said N. Ishwaran, director for ecological sciences of the UN Educational, Scientific and Cultural Organisation which concluded the annual meeting of its World Heritage Committee in Suzhou Wednesday.
"For sites in Europe, Asia and America, where access is easy, tourism can become a threat unless it is monitored."
Being inscribed on UNESCO's prestigious World Heritage List often brings tourists flocking to see sites considered to be of the most "outstanding universal value" in the world.
In China , the ancient walled city of
Pingyao in northern Shanxi province saw tourism revenue rise from a mere 180,000 yuan (21,680 dollars) to five million yuan a year after it was listed as a world heritage site in 1997.
"Listing on the Heritage List brings tourism pressure. Everyone wants to go there," said Jing Sheng, a Chinese official working with the UN group, pointing to the Taj Mahal in India as a prime example.
Some 800,000 overseas visitors -- a third of all foreign tourists to India -- visit the Taj Mahal and other sites in Uttar Pradesh which prompted local authorities to propose a garish tourist complex near the majestic monument. It was only aborted last year when the Supreme Court stepped in after a public outcry, with charges brought against prominent politicians and bureaucrats linked to the project.
Jing said China was among one of the worst cases because cash-strapped local officials often use the site listing as a way to increase their revenue.
"Many local governments see economic development as very important. They don't take a lot of effective measures to protect the sites," Jing said.
China and India also have a unique problem with their huge populations.
Famous sites in the two countries would attract massive numbers of tourists even if they were not on the World Heritage List simply because of the enormous populations in these countries, he said.
"It also has to do with economic growth," Jing said. " China has 1.3 billion people. When people have money, they all want to travel. You can't prevent them from going."
The centuries-old Buddhist art painted in the Mogao Caves in northwestern China , for example, is under threat from the crowds of visitors with management forced to restrict the number of tourists entering the caves.
But UNESCO officials also stress that tourism is necessary to raise funds to protect sites.
"If a site is unexploited, there are no funds to manage it," said Roni Amelan, a spokesman for the Suzhou meeting where 34 sites were added to the Heritage List, bringing the total to 788.
Tourism played a part in Cambodia's celebrated Angkor Wat temple complex being removed from UNESCO's "in danger" list during the meeting, Amelan said.
One of the problems of protecting Angkor was lack of money to hire local residents to work as guards and to pay them enough to prevent them and others from looting the site and selling artefacts overseas.
"Tourism is absolutely crucial. Without tourism, it wouldn't have been able to protect Angkor. The arts market would have continued unbridled," he said.
Putting sites on the List also generates national and local pride as well as a sense of responsibility by local residents to protect it.
"You don't kill the chicken that lays the eggs," said Amelan.
The Committee, meanwhile, subjects the sites listed to constant review, which is why those on the World Heritage List sometimes also end up on the "in danger" list.
Sites harmed by development or other problems are considered in danger -- which is intended to rally funding and other efforts to rescue them.
Thirty-five sites on the World Heritage List are on the "in danger" list.
