When archaeologists first uncovered the 5,000-year-old ruins of Mohenjo Daro, they made one of the greatest discoveries of the 20th century: the world’s only surviving Bronze Age metropolis. Now the once lost city is in danger of disappearing again as its clay wall houses, grid system roads, great granaries, baths and drainage systems crumble to dust, a victim of government neglect, public indifference and tourists’ fears of terrorism.

When discovered, in 1924, the site belonged to the colonial India, part of the British Empire, where archaeologists were seen as national heroes -blends of devoted scholars seeking to uncover the secrets of the past and intrepid explorers aiming to glorify the Crown. Today it lies in Pakistan, where the need to solve problems such as poverty and political instability leaves the preservation of monuments far behind in the State’s priority list. Yet, there is hope as Pakistani authorities alongsite international officials arwe drawing an action plan which will save the ancient site.

What’s the story in Mohenjo Daro?

Mohenjo Daro was a major centre of the pre-Hindu Indus civilisation, which dates back to 3000 BC. Its estimated 40,000 inhabitants were contemporaries of Bronze Age civilisations in ancient Egypt, Mesopotamia, and the Yellow River settlements of China. But while their archaeological legacies were mostly of wealthy rulers and “God-Kings”, Mohenjo Daro has yielded evidence of a society that valued good roads, clean water and a system of law.

Excavation teams led by Sir John Marshall, the director general of the Archaeological Survey of India, and his successors, scraped away thousands of years of mud to uncover an almost perfectly planned city, and evidence of how its inhabitants lived.

Separate drains for rainwater and sewage, covered with limestone slabs to repel insects, ran on a gentle gradient, demonstrating the accomplishment of its engineers. Its masons built wells for drinking water and bathrooms in every home while polishing the tiles of its grand ritual bath to a highly burnished waterproof glaze.

The pool was only partly roofed so the uncovered water could be purified by sunlight. It had a clear class structure with “well-to-do” neighbourhoods of large houses with courtyards and guest rooms opening on to wide boulevards for bullock carts. Its citadel was home to a pillared assembly hall for debates and consultation.

A granary, where wheat and barley were stored on raised plinths to protect them from floods, revealed its good governance — provision was made to feed the city in lean times. Excavators found a water cooler area in the citadel — a square platform dented by the impressions from giant earthenware pots — where its officials could gather and gossip.

There are also clay litter bins on its narrow residential lanes. More than 40,000 artefacts recovered from the excavations have made a collage of the lives of Mohenjo Darans. They include a celebrated bronze statue of a semi-naked dancing girl, perfectly shaped clay urns, platters, ovens that highlight a culinary culture and stone weights and measures that indicate a sense of fairness. A set of carved seals hints at a revenue collection system, while hand-carved figures such as chess pieces and clay toy animals reveal the city’s more playful side.

What’s up now?

According to The Sunday Telegraph, archaeologists report that the world’s oldest planned urban landscape is being corroded by salt and could disappear within 20 years without an urgent rescue plan.

Irshad Ali Rid, Mohenjo Daro’s curator, shares the concerns of Unesco – the United Nations cultural body, Pakistani archeologists and Sindh government officials that all could once again be lost without urgent action.

The ruins, he said, are besieged by the area’s hostile elements. Summer temperatures of 124F (51C), winter frosts, torrential monsoon rains and humid air all combine to leave the sun-dried clay bricks with a dusting of salt crystals that dries them out and sucks them to dust.

The site is in effect an island surrounded by flooded rice paddies and the Indus river on which a tiny band of labourers is locked in a losing battle to spray the walls and roads with a protective layer of “sweet”, salt-free mud, and re-point the crumbling mud mortar that holds the bricks together.

Preservation work has been going on since the first major excavations in 1924 and intensified after it was made a World Heritage Site in 1980, but the effort has flagged as scarce government funds have been diverted by earthquakes and floods, officials said.

They need 350 labourers, as well as masons, supervisors and technical staff, but on the day The Sunday Telegraph visited there were just 16 men wheeling barrows of mud to shore up the walls.

Jawad Aziz, a Unesco heritage expert, said the need for action is vital. “I’ve visited the site and seen the bricks,” he said. “They will be crumbling down, so it’s very urgent.”

Dr Asma Ibrahim, a leading Pakistani archaeologist, said she was pessimistic. “There is no department with expertise, no decisions taken for the last two years,” she said. “The way things are going, it will survive maybe only another 20 years.”

Action!

Last week, international experts and Pakistani officials met in Karachi to draw up a plan to save the site, stabilise its funding and promote awareness of a wonder of the ancient world. They now plan to undertake an intensive conservation programme, a survey to establish how much of the ancient city is still underground and a plan to rebury those sections of the recovered ruins most under threat.