HIDDEN behind the fashion boutiques of Mahatma Gandhi Marg in Lucknow is an architectural gem. The mausoleum of Amjad Ali Shah, a king of Oudh, was built in the 1840s in Indo-Islamic style. Though large, it is delicate, with fine flowers in red plaster over the archways. But Mohammad Haider, a trustee of the mausoleum, mostly spies threats to the monument. He stalks the courtyard, snapping pictures of parked cars and ticking off a building labourer for dumping a large pile of rubble. “Illegal,” he says. “All illegal.”

India has an enormous number of beautiful old buildings and an instinct for preserving them, which it inherited partly from its colonial rulers. Unfortunately, the country also has a corrosive climate, a growing crush of people and cars in its cities and a bureaucracy that is sadly not up to the task of preservation. Its heritage is crumbling. But in Lucknow, a northern city blessed with many historic buildings, that is starting to change.

In the early 20th century India’s British rulers drew up a list of monuments worth protecting, which has hardly changed over the years. Today the Archaeological Survey of India (ASI) oversees some 3,600 sites, with a heavy emphasis on colonial cemeteries. The Amjad Ali Shah mausoleum made the cut, along with 60 other monuments in and around Lucknow. Many others did not. Not surprisingly, the British did not list the Rifa-e-Aam Club, an important nationalist hangout. Once glorious, it is now in an awful state. One wing has become a hospital, while squatters inhabit other rooms. The courtyard doubles as a bus station and a rubbish dump.

Even an ASI listing is no guarantee that a building will be preserved. One of Lucknow’s finest buildings, the Chhota Imambara (pictured), was recently “repaired” with modern cement, wrecking its subtle plasterwork. Mongooses scurry in and out of protected buildings; crows nest in rotting cupolas. It can be hard to find artisans who know how to handle traditional plaster and other authentic materials, says N. K. Pathak, the ASI’s superintending archaeologist in Lucknow. Some conservation architects say the ASI simply isn’t up to the job.

Yet there are signs of a turnaround. The national government has increased the penalties for damaging protected buildings and stiffened a 100-metre exclusion zone around monuments, where (in theory) nothing can be built. Some of Lucknow’s monuments are now being sensitively repaired. There is even slight evidence to suggest that antiquity is becoming a selling point, rather than an irksome obstacle to development. Perhaps the best-preserved colonial building in Lucknow is Constantia, owned by an elite private school.

Above all, Lucknow has Mr Haider. A one-man preservation movement, he drives out encroachers, harries the ASI and files endless petitions to the courts (when not defending buildings, he works as a corporate lawyer). In the past few years he has driven four car-repair shops from the courtyard of the Amjad Ali Shah mausoleum. But the battle never stops. As your correspondent leaves the courtyard, two labourers with baskets of rubble on their heads turn to go inside.