For many centuries, it was a curse that saved the river.

It was a series of curses, actually — a centuries-long string of unrelenting bad news in this rugged, hidden corner of northern India's industrial belt. There was an actual curse at first, a longheld belief that the Chambal River was unholy. There was the land itself, and the more earthly curse of its poor-quality soil. And above all there were the bandits, hiding in the badlands and causing countless eruptions of violence and fear.

But instead of destroying the river, these things protected it by keeping the outside world away. The isolation created a sanctuary.

It is a place of crocodiles and jackals, of river dolphins and the occasional wolf. Hundreds of species of birds — storks, geese, babblers, larks, falcons and so many more — nest along the river. Endangered birds lay small speckled eggs in tiny pits they dig in the sandbars. Gharials, rare crocodile-like creatures that look like they swaggered out of the Mesozoic Era, are commonplace here and nowhere else.

Today, tucked in a hidden corner of what is now a deeply polluted region, where the stench of industrial fumes fills the air in dozens of towns and tons of raw sewage is dumped every day into many rivers, the Chambal has remained essentially wild.

But if bad news saved the river, good news now threatens to destroy it. The modern world, it turns out, may be the most dangerous curse of all.

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SAGES AND BANDITS

The fears that shaped this region go back more than a thousand years, to when sages said the Chambal (the term refers both to the river and the rugged land around it) had been cursed and villagers whispered that it was unholy. In a culture where rivers have long been worshipped, farmers avoided planting along the river's banks.

"People always said things were different in this area," says a laborer working along the Chambal River on a hot afternoon. He is thin, with the ropy toughness and the distrust of outsiders so common here. He gives only his first name, Gopal. "People," he says, "were afraid to come."

A few centuries later the bandits arrived, men who hid in the maze of riverside ravines and kept outsiders away for generations.

They were the last true protectors of the Chambal, it turns out.

For hundreds of years, the outlaws ruled the labyrinth of scrub-filled ravines and tiny villages along the river. Spread across thousands of square miles, the Chambal badlands is a place where a dirt path can reveal a tangle of narrow valleys with 100-foot-high walls, and where a bandit gang could easily disappear.

The bandits' power — rooted in caste divisions, isolation and widespread poverty — was enormous. Countless governments, from Moghul lords to British viceroys to Indian prime ministers, vowed to humble them. Countless governments failed.

As India modernized — as British rule gave way to independence, and a modern nation began to take shape — the Chambal remained a place apart, a feared region where politicians seemed more like criminals and where, in most villages, bandits were the true power.

"We were so isolated for so long," says Hemrudra Singh, a soft-spoken aristocrat with a crumbling family fort overlooking the Chambal River from the village of Bhareh. He understands that isolation well. Until 10 years ago, Bhareh could only be reached by boat during the monsoon season.

Only in the late 1990s did life in the Chambal begin to change significantly. Ancient dirt paths became paved roads, prying open villages that had been isolated for centuries.

The bandits' local political patrons were driven from power. Their foot soldiers were killed in shootouts with police, and their hideouts were forced deeper into the ravines by the spread of new roads. The last famed bandit, Nirbhay Gujjar, was killed by police in 2005.

Today, cellphone towers and motorcycle dealers and satellite TVs are everywhere. New businesses and new schools have opened, ushered in by years of Indian economic growth. Farmers struggling with the poor soil now have fertilizers and tractors.

In so many ways, that has been good news. Poverty remains widespread across the Chambal, but there are more roads now to get crops to market, and mobile phones to call the doctor when someone gets sick. Unemployment remains rampant, but there are occasional new jobs.

With the good, though, came troubles that threaten the Chambal and its wildlife: polluting factories, illegal sand mining and fish poachers who hack at gharials with axes when the animals get tangled in their nets. As India's population and economy grows, more people are moving closer to the river.

Suddenly, the Chambal was no longer synonymous with lawlessness. Instead, it meant cheap land and untapped resources. Quickly, people began to come.

And almost as quickly, the problems began.

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THE NEW CURSE

The garbage multiplied. So did construction projects near the river and, with them, industrial pollutants. Torn plastic bags now sometimes blow through the ravines, and small stone quarries dump refuse into creeks that feed the Chambal.

In 2007 and 2008, more than 100 dead gharials washed up on riverbanks — perhaps 25 percent of the world's wild gharials at the time. While scientists have never been able to pinpoint the cause, and the population has grown back to a degree, most experts believe pollution introduced a toxin into the river.

"In the old days, there weren't many people here to interfere with the river," said Dr. Rajiv Chauhan, a scientist and Chambal River expert with the India-based Society for Conservation of Nature. "But with the bandits gone, the pressure on the river is now just too much."

In theory, the wildest parts of the river are protected. A narrow 250-mile stretch of the Chambal was declared an official sanctuary in the late 1970s, closing it to everyone but longtime villagers, approved scientists and the handful of tourists who make it here.

But India's wildlife agencies are woefully undertrained and underfunded. Forestry officials often need to borrow boats to patrol the river. Banditry may have faded, but corruption is rampant: Locals who illegally cut firewood in the sanctuary pass forestry department checkpoints without challenge.

More factories are being built upstream from the sanctuary, and their pollutants are leaking into the river. Increased farming has caused a spike in dangerous fertilizer and pesticide runoff, scientists say. Billions of gallons of water are siphoned away for irrigation.

The most immediate worry is illegal sand mining, which can strip away thousands of tons of riverbank on a single day, causing immense amounts of silt to spill into the river, upsetting its delicate ecology.

Demand for sand has soared across India in recent years as the economy has grown, leaving an emerging middle class clamoring for housing. Since most new Indian housing is made of concrete, and concrete requires sand, the surge in building has given rise to a sprawling network of black-market sand dealers. The "sand mafia," as the Indian media calls it, has no qualms plundering the easy pickings along a wild riverbank.

Take a boat along the Chambal River on nearly any day, and the mafia's power quickly becomes clear.

Not far from the village of Bhopepura, dozens of tractors regularly snake down a dirt road to the river, pulling trailers filled with wiry, shovel-wielding men who hop down once they reach the riverbank. These are the sand mafia's labor force, men who can earn $15 for a long, exhausting day of work. That is good pay around here.

The mining is illegal, but the laborers say their bosses have paid off local officials. While none of the miners will give their full names, they also make no effort to hide what they're doing. The mining area, perhaps 30 acres in total, can be easily seen from both banks of the river. While the men work, tractors rigged with loudspeakers blare Bollywood songs.

There's a calm beauty to the scene. Local villagers pass by, leading camels that leave footprints the size of dinner plates in the soft sand. When the breeze picks up, the camel bells clang.

But people like Singh, the aristocrat, worry of tomorrow. Asked if he is optimistic about the area's future, Singh simply looks at the floor and shakes his head.

The laborers, poor men who spend most of the year working on tiny farms, are concerned with making extra money, not with wildlife. And that is the biggest curse that the Chambal faces today: The path of progress, sometimes, leaves little room for anything else.

"What is a sanctuary?" says Gopal, the river laborer, his voice dripping with disdain. "What is a mammal? What is a bird? I don't have time to worry about these things."

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EDITOR'S NOTE — Tim Sullivan is senior Asia correspondent for The Associated Press, based in India. Follow him on Twitter at http://twitter.com/SullivanTimAP