The Peruvian government has come up with an emergency plan to preserve the mountain-top Inca citadel Machu Picchu and the surrounding national park from the ravages of too many tourists and possible landslides.

　　The $132.5m (?70m) plan is to be studied by Unesco and the World Bank at a three-day meeting in Lima beginning on Saturday.

　　Machu Picchu is the most visited archaeological site in Latin America. It has been a Unesco world heritage site since 1983, but the UN's cultural organisation made it clear last year that if something were not done soon it would be put on the list of sites at risk. This would be a highly shameful step towards being kicked off altogether.

　　"We welcome this plan very much, it was long awaited," Unesco's Latin America unit manager, Ron van Oers, told the Guardian from the organisation's headquarters in Paris. "It looks like a possible way out of the tunnel."

　　Mr Van Oers said Unesco had expressed its concerns about the site to the Peruvian government through informal channels for about 10 years. He blamed a lack of governmental coordination, rather than active resistance, for the delayed response. "There are just so many people involved - the cultural ministry and the tourism authorities, the environment ministry, urban planning - they all have different mandates and different interests," he said. "Things reached a limit last year."

　　The most immediate problem facing Machu Picchu is the huge number of badly managed tourists.

　　Built probably around 1450 by the Incan ruler Pachacuti Inca Yupanqui, the city was inhabited until the Spanish conquest of Peru in 1532 and then abandoned and forgotten. The ruins, near the southern Peruvian city of Cuzco, were discovered for the modern world by the American explorer Hiram Bingham in 1911, by which time they had been entirely covered by thick tropical forest.

　　Less than a century later, nearly half a million tourists every year trample through the stone ruins, 2,560 metres above sea level.

　　A significant minority hike to the site through spectacular Andean scenery along the Inca trail, which is also suffering serious damage from overuse. The rest approach via a railway from the southern Peruvian city of Cuzco which ends in a small unplanned town called Aguas Calientes.

　　There is concern about the pollution caused by minibuses shuttling tourists up and down the mountain between Aguas Calientes and the site, as well as the uncontrolled development of the town.