More than 2,000 years ago, when India's Emperor Ashoka made a pilgrimage to Kathmandu Valley to spread Buddhism, he left his mark by building four chaityas. Also known as stupas, they mark the four cardinal points around Patan, giving the holy city its celestial coordinates.

Originally, the stupas were built on stacks of bricks, which have gradually become grassy mounds in the east, west, north and south of Patan. The ancient monuments still stand at Pulchok, Ebihi Tol, Lagankhel and Imadol. The Ashoka chaityas were built in 250 BC, when Patan was known by its Newari name, Yala, and they could well be the most ancient religious monuments in Nepal.

Historian Niels Gutschow says the chaityas were built to define the limits of the ancient town's 'meaningful sacred space against the profane and non-significant territory around. In ancient times, it would probably be possible from the top of any one stupa to see the other three.

This is why it is sad to see the holy and historic sites being desecrated by urban sprawl, ugly pedestrian bridges, crass hoardings and real estate speculators encroaching on guthi land.

The west chaitya in Pulchok is the smallest of the four and is now dwarfed by apartment blocks, an overhead bridge and a huge shopping complex under construction across the street. A stone's throw away is the Lalitpur sub-metropolitan office, with its tastelessly grandiose architecture, which is supposed to preserve the town's heritage.

With no mayor, the municipality is leaderless and rudderless. "Things would have been better if there was a mayor," laments a staffer. Two years ago, when Mayor Buddhi Raj Bajracharya ordered the demolition of some houses built illegally near the stupa, he faced stiff opposition from private builders.

Even the government's Department of Archaeology does not have the power to dismantle the buildings or even stop illegal new construction. "The law ties our hands," says an officer. The land around all the four stupas has been legally acquisitioned, and it seems the landowner can do anything with his property: build a commercial complex, a car park or lease the land for a shop or a restaurant.

The government's helplessness is apparent in Lagankhel, where the largest of the four Ashoka stupas stands. This stupa is built on higher ground, so it currently dominates the skyline with no buildings to obstruct its spiritual ambience. This will soon change though as an empty plot of land owned by the semi-government Namuna Machindra Secondary School is planning a huge two-storey complex to raise funds for the school.

The building plan has already provoked a dispute between the school management committee and local residents. "We will do everything in our power to stop the school from destroying the stupa," says Uday Man Shrestha, president of Lagankhel Environment Development Organisation, which has been actively campaigning against the school's plan.

Shrestha says the disputed land used to be a holy moat that surrounded the stupa and has religious significance. Every year at the end of the Rato Macchendranath festival, priests release a pair of sparrows and a pair of fish into the water to send a message to Lord Indra about the successful completion of the festival.

"This centuries-old tradition will die because of some greedy individuals," says Ajay Lama from Lagankhel Youth Club, which is also campaigning to protect the ancient site.

The school says construction will not jeopardise the holy site at all and maintain there was no holy lake on the land which the government handed over to the school in the late 1970s. School management says it decided to build on the site after locals started dumping garbage in the area. "Nothing can stop us, we have all the documents and permission," says the school's legal adviser, Purosattam Dhungana. "Besides, why aren't the activists stopping the construction of the tall buildings all around?"

The Department of Archaeology says it tried to stop construction but the school had an air-tight legal case. Ex-mayor Bajracharya is incensed. "I would have never allowed the construction if I was still mayor. All this is happening because there is no mayor," he says. However, it was under Bajracharya's watch that the unsightly overhead bridge was built in front of the Pulchok stupa.

For the local community and conservationists, the issue is not just the school building or an overhead bridge, but that it will pave the way for even bigger buildings and more commercialisation. The Lagankhel stupa is the only one that still has some character left.

The grounds of the east Ashoka stupa in Ebihi Tol have narrowed. Most of the houses here are taller than the stupa, which seems to have lost its religious significance for the locals. When we asked for directions, most couldn't even show us the way to the chaitya. "The blame goes to the Lalitpur municipality, which allowed people to illegally build houses on encroached land. Now it is impossible to remove the buildings," says local resident, Lucheman Maharjan, who has built his own shop attached to the stupa's perimeter wall.

The north Ashoka stupa in Imadol is in an even poorer state. Private house owners have encroached on the land and built brick blocks. Nearby is an empty shell that the VDC spent Rs 1.6 million on building a water tank which was never completed. Local residents don't even bother keeping the holy site clean, flies swarm all over the garbage. The stupa's grassy mound has become a pasture for goats and for children to play.

"It is so embarrassing whenever tourists come all the way here to look for the stupa," says local resident Danu Sunuwar. "Nothing of this will be left when our children grow up."