Up to 300 trucks a day take their fill of sand at a mine on the Sone River in Bihar state. India’s construction boom is stripping large volumes of sand, a vital ingredient in concrete, from its rivers. Environmentalists say the extraction is unsustainable, harming local hydrology and wildlife.

DEHRI ON SONE, BIHAR, INDIA” You must be journalists? Are you interested in sand mining?”

We are in trouble.

It is the local muscle. There are four of them. Thick-armed, hooded-eyed men who have braked their white SUV to interrogate my walking partner, Siddharth Agarwal, and me at a dhaba, a roadside eatery in northern India. Our plastic table quakes from the passage of heavy trucks. What do these columns of vehicles carry? A torrent of mined sand: the dredged-up riverbeds of the Sindh River and its tributaries in destitute Madhya Pradesh state. Every truckload is bound for distant construction sites. Much of the cargo is illegal. Sand is a lucrative commodity in India. It fuels a black market that is both preyed on and protected by goons. Sand miners have killed law enforcement officers who have attempted to halt the strip-mining of India’s rivers. They have murdered reporters who have exposed the forbidden practice of excavating waterways. Agarwal and I exchange glances.

“We’re looking for journalists to help us,” one of the burly men says over the growl of the traffic.

Really?

“Yes. The other guys down the road are extorting too much from the trucks,” he tells us. “They leave us little money. We have documents to prove it. It’s not fair. We want to go to the media.”

India. Here, everyone owns a grievance—even the sand mafia.

Sand might seem a strange contraband to most of the world. The lowly resource is little more than ground-up rocks, tiny grains of silica and quartz washed down rivers from eroding mountaintops. Illegally mined sand does not conjure the dark romance of, say, blood diamonds, or the pathos of trafficked wildlife. Moreover, there appears to be an infinite supply of the stuff. Only there isn’t. 

Our modern civilization is built on sand: concrete, paved roads, ceramics, metallurgy, petroleum fracking—even the glass on smart phones—all require the humble substance. River sand is best: grains of desert sand are often too rounded to serve as industrial binding agents, and marine sand is corrosive. A United Nations study calculates, however, that humankind’s total consumption of sand—more than 40 billion tons a year—is now double the amount of sediments being replenished naturally on the Earth by the sum of the world’s rivers.

Today, sand has become so valuable that it is shipped enormous distances: Australia sends boatloads of sand to Arabia for land reclamation projects. China, the world’s builder, is also the planet’s sand glutton. Between 2011 and 2014 alone, the Chinese poured more concrete—made up largely of sand—than the United States used during the whole of the 20th century. With its exploding megacities, India ranks second in the world’s sand consumption.

I see evidence of that gritty appetite often on my 2,300-mile foot traverse through the country.

Backhoes peel away the sandy beds of scores of rivers, exposing bare channels of bedrock, silt, and clay. Rickety barges float mounds of sand to makeshift ports. India’s roads are warped and potholed by overladen armadas of sand trucks. The environmental toll of this poorly monitored industry is incalculable.

“Sand mining can change the course of rivers,” says Rishikesh Sharma, a retired government biologist who has worked for years at the National Chambal Sanctuary, a premier Indian river preserve that shelters endangered crocodiles called gharials as well as river dolphins. “The mining hurts wildlife by removing basking and egg-laying habitat.”

Rampant sand mining directly harms people too.

Stripping rivers of their sand causes water tables to drop—an ominous concern in India, where millions already face historic water shortages. Massive sand mining also has eroded river deltas across Asia, exposing coastal communities to severe land loss, and worsening the effects of climate change-induced sea level rise.

Indian authorities insist they are imposing order.

The state of Uttar Pradesh declared a mining ban until its rivers can recharge their sandy principal. Other places prohibit large-scale industrial operations. Permits cap sand harvests—in theory. But profits from India’s construction boom help keep the sand mining frontier lawless.

On the Betwa River in Madhya Pradesh, we meet wary miners who live in raw camps. They tell of workers and tents washed away in sudden dam releases. On the Ganges, in Uttar Pradesh, roving backhoe crews chew into the sands beneath funerary ghats—riverside pyres where Hindus cremate their dead. And at a single large operation on the Sone River, in Bihar, thousands of men toil in shifts to pack 300 trucks a day with sand, earning 500 rupees ($7) a truckload: twice a field hand’s wages.

“It’s impossible for the Sone to run out of sand—how can you say that?” says Vinay Kumar, a 22-year-old laborer. “Every monsoon brings new sand.”

But the bed of the Sone, admits Kumar, has dropped at least six feet since he began mining as a teenager.

Back on the Sindh River, meanwhile, the frustrated gang of muscle men—the sand truck extortionists who grill partner Agarwal and me at the roadhouse—know better.

He is blunt. Candid. He identifies himself as Rajiv Yadav.

Yadav says India’s sand mafia will not go away soon because it includes many business people and politicians. The police’s cut of the “royalties” alone, he claims, inflates the price of his region’s finite river sands from 15,000 rupees (about $200) a truckload to between 40,000 and 80,000 rupees. It is outrageous. All he asks for is fairness—his share. And once the natural sands are gone, then perhaps new sand can be made artificially, by crushing rocks. Or bricks.