This story appears in the August 2017 issue of National Geographic magazine.

At 65, Moolchand, bandy-legged and white-haired, has no problem rising for his predawn hunts. In fact he revels in them.

“I hide along the lane with my flashlight,” he says in a low, excited voice, gesturing down the main road of Gaji Khedi village, in India’s Madhya Pradesh state. “And I look for people walking with a lota.”

A lota is a water container, traditionally made of brass but these days more often of plastic. Spied outdoors in the early morning, it all but screams that its owner is headed for a field or roadside to move his or her bowels—the water is for rinsing.

“I give chase,” Moolchand continues. “I blow my whistle, and I dump out their lota. Sometimes I take it away and burn it.” Moolchand sees himself as defending a hard-won honor: The district has declared his village “open defecation free.” “People get angry and shout at me when I stop them,” he says. “But the government has given villagers lots of help to construct a toilet, so there is no excuse.”

Defecating in the open is as old as humankind. As long as population densities were low and the earth could safely absorb human wastes, it caused few problems. But as more people gathered in towns and cities, we gradually learned the link between hygiene and health and, in particular, the importance of avoiding contact with feces. Today open defecation is on the decline worldwide, but nearly 950 million people still routinely practice it. Some 569 million of them live in India. Walk along its train tracks or rural roads, and you will readily encounter the evidence.

In 2015 the United Nations called for an end to open defecation by 2030. It’s not impossible to make great strides: Vietnam, for example, has all but eliminated the practice over the past few decades. Achieving the global milestone, number six on the UN’s list of Sustainable Development Goals, would radically improve public health: Diseases caused by poor sanitation and unsafe water kill more children, some 1.4 million per year, than measles, malaria, and AIDS combined. It also would help alleviate poverty and hunger and improve education. Sick kids miss school, and so do menstruating girls whose schools lack a clean and safe toilet.

India has been grappling with the problem since before it won independence from Great Britain in 1947. “Sanitation is more important than independence,” Mahatma Gandhi said, urging his compatriots to clean up their act. To some extent they have: The percentage of Indians who defecate in the open has declined substantially in recent decades. But with the population growing rapidly, census data suggest that most Indians now live in places where they are more exposed to others’ feces, not less.

The current prime minister, Narendra Modi, campaigned with the slogan “toilets before temples.” In 2014, before the UN set its 2030 goal, Modi declared his intention to end open defecation in India more than a decade earlier, by October 2, 2019—Gandhi’s 150th birthday. He allotted more than $40 billion for a latrine-building and behavior-change blitz called Swachh Bharat Abhiyan (Clean India Mission), for which the World Bank threw in another $1.5 billion in loans.

Modi aims to build more than 100 million new toilets in rural areas alone by 2019. Whether he’ll succeed is one question; whether the toilets will make much difference is another. Indian governments have been building low-cost latrines for at least 30 years. Millions of these simple, freestanding structures dot the countryside, but many are crumbling. And many more are used to shelter small animals or to store tools, bikes, and grain—while their owners head out into the fields with their lotas. In India deep-seated attitudes may present an even bigger barrier to improving sanitation than a lack of pipes and pits.

In the side yard of every mud-plastered home in the hamlet of Jawda, several hours southwest of Moolchand’s village, stands a spanking-new concrete outhouse the size of a large phone booth, painted salmon pink. Inside, a white ceramic squat pan funnels waste—sluiced by water from a bucket or lota—through a pipe into a four-foot-deep pit. The brick-walled pit is designed to collect feces while allowing liquids to seep into the earth. A small pool of water cradled in a U-shaped bend in the pipe helps contain smells and block insects from the pit. Flies breeding and feeding on feces are one of the main vehicles delivering infectious organisms back to humans; one gram of feces can contain 10 million viruses, one million bacteria, and 1,000 parasitic cysts. They infect us through tiny openings in our skin or by contaminating food and water.

The health toll in India is staggering. Diarrhea kills over 117,000 children under age five each year. Millions more struggle on with chronically infected intestines that don’t absorb nutrients and medicines well. The misery cycles on: Underweight women give birth to underweight babies, who are more vulnerable to infections, more likely to be stunted, and less able to benefit from vaccines. In 2016, 39 percent of Indian children under age five were stunted.

The Swachh Bharat mission offers each household about $190 to construct a pit latrine—far more than other developing nations spend. In Jawda, however, nobody uses the latrines. “It’s for washing clothes or bathing,” says a woman in a pink-and-black sari, resting on a rope-strung cot in the shade. “We have a lot of open space. Why shouldn’t we use that?” Grassy fields dotted with wildflowers surround her village.

Cleaning Up an Unsanitary World The percentage of people defecating in the open air declined worldwide from 1990 to 2015, with the most dramatic reductions in some of the least developed countries. Yet nearly 950 million people still practice this public health hazard—a challenge augmented by population growth. Cleaning Up an Unsanitary World The percentage of people defecating in the open air declined worldwide from 1990 to 2015, with the most dramatic reductions in some of the least developed countries. Yet nearly 950 million people still practice this public health hazard—a challenge augmented by population growth. Cleaning Up an Unsanitary World The percentage of people defecating in the open air declined worldwide from 1990 to 2015, with the most dramatic reductions in some of the least developed countries. Yet nearly 950 million people still practice this public health hazard—a challenge augment- ed by population growth. North America ASIA Europe Haiti INDIA Vietnam 3 1 4 5 8 2 9 Africa 6 SOUth America Countries with highest rates 1. Eritrea 2. South Sudan 3. Niger 4. Chad 5. Burkina Faso 6. Sao Tome and Principe 7. Solomon Islands 8. Benin 9. Togo 10. Namibia Percentage of population that defecates in the open 7 10 Australia More than 40 25 to 40 10 to 24.9 1 to 9.9 Less than 1 No data ← Drag to explore → North America Europe ASIA Haiti INDIA Vietnam 3 1 4 5 8 2 9 Africa 6 SOUth America 7 10 Australia Countries with highest rates 1. Eritrea 2. South Sudan 3. Niger 4. Chad 5. Burkina Faso 6. Sao Tome and Principe 7. Solomon Islands 8. Benin 9. Togo 10. Namibia Percentage of population that defecates in the open More than 40 25 to 40 10 to 24.9 1 to 9.9 Less than 1 No data Percentage of population that defecates in the open More than 40 25 to 40 10 to 24.9 1 to 9.9 Less than 1 No data Countries with highest rates 1. Eritrea 2. South Sudan 3. Niger 4. Chad 5. Burkina Faso 6. Sao Tome and Principe 7. Solomon Islands 8. Benin 9. Togo 10. Namibia Making Gains Vietnam has nearly eradicated open defecation. UN statistics based on toilet construction show India has made progress too—but some experts dispute the extent, arguing in part that many of the latrines that have been built go unused. Change in open-defecation rates Vietnam India 100% 75% 50 44% 39% 0.7% 0 1990 1990 2015 2015 Making Gains Change in open-defecation rates Vietnam has nearly eradicated open defecation. UN statistics based on toilet construction show India has made progress too—but some experts dispute the extent, arguing in part that many of the latrines that have been built go unused. Vietnam India 100% 75% 50 44% 39% 0.7% 0 1990 1990 2015 2015 Making Gains Change in open-defecation rates Vietnam has nearly eradicated open defecation. UN statistics based on toilet construction show India has made progress too—but some experts dispute the extent, arguing in part that many of the latrines that have been built go unused. Vietnam India 100% 75% 50 44% 39% 0.7% 0 1990 1990 2015 2015 Sanitation And stunting In many developing countries, the prevalence of open defecation has a terrible effect on children: It exposes them to illnesses that cause malnutrition and stunt their growth. Number of people openly defecating 100 million 10 million 1 million Percentage of children under five who are stunted 60% 40 30 20 50 10 Brazil Burundi Dominican Republic Ghana Timor- Leste Indonesia Pakistan Ethiopia Nigeria Eritrea Nepal Togo Haiti Number of people per acre openly defecating 25 Sao Tome and Principe India About 569 million people in India defecate in the open. 50 60% Jason Treat and Matthew W. Chwastyk, NGM Staff; Kelsey Nowakowski Sources: WHO/UNICEF Joint Monitoring Programme for Water Supply and Sanitation; Sangita Vyas, Research Institute for Compassionate Economics Percentage of children under five who are stunted 60% Burundi Sanitation And stunting Timor-Leste India In many developing countries, the prevalence of open defecation has a terrible effect on children: It exposes them to illnesses that cause malnutrition and stunt their growth. Eritrea 50% Pakistan About Ethiopia Nepal 569 million 40% Indonesia people in India defecate in the open. Sao Tome and Principe Nigeria 30% Togo Haiti 20% Ghana Number of people openly defecating 10% 100 million Dominican Republic 10 million Brazil 1 million 25 50 Number of people per acre openly defecating Jason Treat and Matthew W. Chwastyk, NGM Staff; Kelsey Nowakowski Sources: WHO/UNICEF Joint Monitoring Programme for Water Supply and Sanitation; Sangita Vyas, Research Institute for Compassionate Economics Percentage of children under five who are stunted 60% Burundi Sanitation And stunting Timor-Leste India In many developing countries, the prevalence of open defecation has a terrible effect on children: It exposes them to illnesses that cause malnutrition and stunt their growth. Eritrea 50% Pakistan About Ethiopia 569 million Nepal 40% Indonesia people in India defecate in the open. Sao Tome and Principe Nigeria 30% Togo Haiti 20% Ghana Number of people openly defecating 10% 100 million Dominican Republic 10 million Brazil 1 million 25 50 Number of people per acre openly defecating Jason Treat and Matthew W. Chwastyk, NGM Staff; Kelsey Nowakowski Sources: WHO/UNICEF Joint Monitoring Programme for Water Supply and Sanitation; Sangita Vyas, Research Institute for Compassionate Economics

In surveys done throughout rural northern India, where open defecation is more prevalent than in the south, people express a keen preference for relieving themselves outdoors. It’s healthier, they say. It’s natural and even virtuous. Many rural Indians consider even the most immaculate latrine religiously polluting; a toilet near the home seems more unclean to them than answering the call of nature 200 yards away. Flies, however, can travel more than a mile.

The children in Jawda know, from visits by community health workers, that toilets are a boon for health. A girl nuzzling a tawny goat explains with great precision how flies and fingers can transfer feces from the field to food and water, sickening villagers. “But if the toilet pits are small,” her mother interrupts, “we’ll have this filth near us. And if we get sick, we have no money to cure ourselves.”

In Khargone District, in southwestern Madhya Pradesh, I walk through the unpaved streets of a hamlet with Nikhil Srivastav, a policy researcher affiliated with the Research Institute for Compassionate Economics (RICE). Led by two Americans, Diane Coffey and Dean Spears, the nonprofit deploys both American and Indian researchers to study the well-being of India’s poor, with an emphasis on children. Trailed by barefoot kids, Srivastav and I step over a thin, smelly stream, in which rat-tailed maggots tumble, and into a neatly swept compound. There we meet Jagdish, a retired tour-bus driver who recently spent 50,000 rupees (about $780) to dig a latrine seven feet deep, instead of the government-recommended four, and finish its superstructure with blue dolphin tiles.

But Jagdish doesn’t make much use of this beautiful chamber. “It’s for my wife and daughter-in-law,” he says. Like many of his neighbors, Jagdish prefers to walk uphill into the bush to perform his daily ablutions. In rural India it’s considered the manly thing to do. Patriarchal advertisements indirectly reinforce that notion, imploring men to build toilets, not for the health of the whole family, but to protect their wives and daughters from sexual harassment out in the bush and from the shame of lifting their saris outdoors. One campaign encourages brides to reject grooms whose assets don’t include a toilet.

And yet, as I saw in Jawda, many rural women ignore these messages and still head outdoors themselves. These women and girls may be reluctant to break with tradition or may feel cooped up inside a latrine, especially one they lack the tools or inclination to clean. Some may also prize the opportunity to get together with their girlfriends. Open defecation, as strange as this may sound to Westerners, offers young women a welcome break from their domestic confines and the oversight of in-laws and husbands.

Jagdish is proud of his latrine, which he built with Swachh Bharat funding and his own savings. His only regret is not digging his pit even deeper. “Fifteen feet would have been better,” he says. Pit latrines have a huge drawback, you see: They fill up. And rather than empty a pit with a shovel or hire a pump truck—or easier still, dig a new latrine, which is standard procedure in other nations—rural Indians, especially in northern India, often opt to build no latrine at all.

Three years ago RICE researchers collected data on latrine use by more than 22,000 rural Indians. The team discovered that 40 percent of households with toilets had at least one member who continued to defecate outdoors; that people with government-funded toilets were twice as likely to defecate in the open as those who built their own; and that families without any toilet at all said they couldn’t afford to build the type they’d actually use. RICE found that privately constructed pit latrines were four to five times larger than the 50 cubic feet recommended by the World Health Organization. “That’s the size used all over the world,” Srivastav says, “and a family of six won’t fill it for five years.” Indians’ ideal pit latrine was larger still: up to 1,000 cubic feet—larger than many Indians’ living space.

Why this obsession with size? “A smaller soak pit will fill up in five months,” Jagdish explains, erroneously. “Then I’d have to call a Dalit”—a low-caste person—“to empty it.”

“Couldn’t you do this on your own?” Srivastav asks. Jagdish shakes his head.

“There would be objections from the community,” he says. “You’d be ostracized for cleaning your own house.”

View Images INDIA After charities spent $28,000 to install a sewer line in Safeda Basti, 62 households constructed and connected private toilets, some of them on rooftops (bottom left). Without other plumbing, however, most residents must still haul water for flushing and handwashing from taps in the street.

That pronouncement points to an answer to the great puzzle of Indian sanitation. Why are India’s open-defecation rates so much higher than those in other developing nations, when India is richer, has higher literacy rates, and has more access to water? What sets India apart, at least according to RICE, are rural Indians’ beliefs about purity, pollution, and caste.

For thousands of years Dalits—formerly known as Untouchables—have been forbidden from drinking at the same wells, worshipping at the same temples, or even wearing shoes in the presence of upper castes. Modern laws against such discrimination are rarely enforced, and poverty and violence still compel Dalits to do the nation’s dirty work. They clear carcasses from roads, placentas from birthing rooms, and human waste from pits and open sewers. Meanwhile higher caste Indians retain their status and supposed superiority in part by avoiding any association with such degrading labors.

In recent years, however, Dalits struggling for equality have begun to shun the sorts of jobs historically used to justify their oppression. And so the cost of emptying a pit latrine has risen as demand for the service has outstripped the supply of willing workers. Given this fraught social and economic landscape, it’s no wonder that some rural Indians save enough money to build a latrine pit so big they’ll never have to empty it. Or that hundreds of millions of them—most of whom could afford a simple latrine—choose to conduct their business in the great outdoors.

The High Price of Modern Hygiene Paid by utility $52.63 Sewers connected to treatment plants are the best way of removing the hazard of human waste, especially in cities. But they’re costly to build and maintain. Collecting sludge from latrines or septic tanks is an alternative—if the sludge is properly managed. Often it isn’t. A private burden Annualized costs per capita for waste treatment in Dakar, Senegal In Dakar, Senegal, sewer systems were found to be nearly five times more expensive than collecting and managing fecal sludge. The latter method, however, costs more for households, which are responsible for their own latrines or septic tanks. $54.64 Paid by others $0.01 Paid by utility $1.86 $11.63 $9.74 $2.00 Paid by others $0.03 Paid by household Fecal sludge management systems Sewer-based systems Schematic of a sewer After the flush Sewer systems require a huge invest- ment in infrastructure to connect all users. The process varies, but each toilet in an urban area must be connect- ed to large underground mains, which then feed into large waste­water treatment plants. Pipes and sewers Primary treatment Aeration tanks Chemical treatment Gravity-fed conduits funnel wastewater from homes and businesses to a treatment plant. In a holding tank, solids settle out of the waste- water. Oils and grease are skimmed off the top. The wastewater flows into aerated tanks, where bac- teria digest the remaining solids and nutrients. In some communi­ties, chemicals such as chlorine are added to kill any remaining bacteria. Waste treatment in Delhi, India Overflowing cities Sewers aren’t guarantees: In Delhi only 56 percent of waste is safely managed, because sewers leak and nearly a third of the booming city isn’t connected. Many latrines empty into open drains, and 4 percent of residents —some 700,000—defecate outdoors. Input Containment Emptying Transport Treatment End Use Safely managed 56% Sewers 68% Latrines 28% Unsafely managed 44% Jason Treat, NGM Staff; Kelsey Nowakowski Sources: Linda Strande, Swiss Federal Institute of Aquatic Science and Technology (EAWAG); Emily C. Rand, World Bank; Centre for Science and Environment, New Delhi Open defecation 4% The High Price of Modern Hygiene Sewers connected to treatment plants are the best way of removing the hazard of human waste, especially in cities. But they’re costly to build and maintain. Collecting sludge from latrines or septic tanks is an alternative—if the sludge is properly managed. Often it isn’t. A private burden In Dakar, Senegal, sewer systems were found to be nearly five times more expensive than collecting and managing fecal sludge. The latter method, however, costs more for households, which are responsible for their own latrines or septic tanks. Annualized costs per capita for waste treatment in Dakar, Senegal Fecal sludge management systems Paid by utility $1.86 Paid by household $9.74 $11.63 Paid by others $0.03 Sewer-based systems $54.64 Paid by others $0.01 Paid by household $2.00 Paid by utility $52.63 After the flush Sewer systems require a huge investment in infrastructure to connect all users. The pro- cess varies, but each toilet in an urban area must be connected to large underground mains, which then feed into large waste­water treatment plants. Schematic of a sewer Gravity-fed conduits funnel wastewater from homes and businesses to a treat ment plant. In a holding tank, solids settle out of the wastewater. Oils and grease are skimmed off the top. The wastewater flows into aerated tanks, where bacteria digest the remaining solids and nutrients. In some communi­ties, chemicals such as chlorine are added to kill any remaining bacteria. Overflowing cities Sewers aren’t guarantees: In Delhi only 56 percent of waste is safely managed, because sewers leak and nearly a third of the booming city isn’t connected. Many latrines empty into open drains, and 4 percent of residents —some 700,000—defecate outdoors. Waste treatment in Delhi, India Open defecation 4% Latrines 28% Sewers 68% Input Containment Emptying Transport Treatment 44% 56% End Use Safely managed Unsafely managed Jason Treat, NGM Staff; Kelsey Nowakowski Sources: Linda Strande, Swiss Federal Insti- tute of Aquatic Science and Technology (EAWAG); Emily C. Rand, World Bank; Centre for Science and Environment, New Delhi The High Price of Modern Hygiene Sewers connected to treatment plants are the best way of removing the hazard of human waste, especially in cities. But they’re costly to build and maintain. Collecting sludge from latrines or septic tanks is an alternative—if the sludge is properly managed. Often it isn’t. A private burden Paid by utility $52.63 In Dakar, Senegal, sewer systems were found to be nearly five times more expensive than collecting and managing fecal sludge. The latter method, however, costs more for households, which are responsible for their own latrines or septic tanks. Annualized costs per capita for waste treatment in Dakar, Senegal $54.64 Paid by others $0.01 Paid by utility $1.86 $11.63 $9.74 $2.00 Paid by others $0.03 Paid by household Fecal sludge management systems Sewer-based systems After the flush Sewer systems require a huge investment in infrastructure to connect all users. The process varies, but each toilet in an urban area must be connected to large underground mains, which then feed into large waste­water treatment plants. Schematic of a sewer Pipes and sewers Primary treatment Aeration tanks Chemical treatment Gravity-fed conduits funnel wastewater from homes and businesses to a treatment plant. In a holding tank, solids settle out of the waste- water. Oils and grease are skimmed off the top. The wastewater flows into aerated tanks, where bac- teria digest the remaining solids and nutrients. In some communi­ties, chemicals such as chlorine are added to kill any remaining bacteria. Overflowing cities Sewers aren’t guarantees: In Delhi only 56 percent of waste is safely managed, because sewers leak and nearly a third of the booming city isn’t connected. Many latrines empty into open drains, and 4 percent of residents —some 700,000—defecate outdoors. Waste treatment in Delhi, India Input Containment Emptying Transport Treatment End Use Safely managed 56% Sewers 68% Latrines 28% Unsafely managed 44% Open defecation 4% Jason Treat, NGM Staff; Kelsey Nowakowski Sources: Linda Strande, Swiss Federal Institute of Aquatic Science and Technology (EAWAG); Emily C. Rand, World Bank; Centre for Science and Environment, New Delhi

Globally most people who defecate outdoors live in rural areas. But in India the number of urban slum dwellers who do so is on the rise, as the population increases and villagers migrate to cities that are lacking in toilets, to say nothing of sewer pipes and treatment plants. Today 157 million people in Indian cities—37 percent of the urban population—lack a safe and private toilet. It’s a crisis and an opportunity, says Pragya Gupta of WaterAid India, a charity that works on sanitation: “It’s easier to do behavior change in slums because the need is right there, in your face.”

Gupta and I are visiting Safeda Basti, a slum in East Delhi’s Geeta Colony. The narrow streets bustle with commerce, jousting children, and women washing dishes in the open doorways of ramshackle homes. Laundry hangs from electrical wires, and toddlers crawl just inches from open drains. Lacking household toilets, people either relieve themselves in rubbish-strewn lots or queue up at a nearby community toilet complex.

I ask a group of women about the benefits of such facilities, expecting to hear about convenience, privacy, and safety. Instead I learn they’re universally reviled. “We have to stand in a long line because there aren’t enough toilets,” a mother says, “so our kids are late to school.” “People fight,” her neighbor chimes in. “Girls are harassed at night.” The squat pans are dirty, faucets broken, soap absent. “We feel suffocated indoors,” a young woman says. Some complexes don’t have roofs, a misery during the monsoon, and some lack electricity. As if that weren’t bad enough, the complexes charge a few rupees per day and close between 11 p.m. and 4 or 5 a.m. At night, people in need do what they must.

Batting away flies, I follow a street drain that grows wider as it nears a fetid canal at the colony’s edge. Eventually it will pour into the Yamuna River, a tributary of the Ganges. Drains such as this one collect wastewater from cooking and cleaning, but they also fill with litter, food scraps, and the urine and feces of children who can’t make it as far as the toilets. In stagnant reaches, methane bubbles up through the gray-green water, and the stench of rotten eggs—hydrogen sulfide—wafts into homes. With so many people so close together and so much fecal matter in play, it’s not surprising to learn from a local health worker that the colony’s major medical problems are diarrhea and worms.

View Images HAITI In Port-au-Prince, Exilien Cenat stands above the hole in a communal outhouse. Working at night to avoid public scorn, he empties the pit with his hands and a bucket, collects the waste in bags, and dumps the bags into ditches or canals. Flush toilets and sewers would be a more sanitary solution, but they’re simply too expensive.

In other Delhi slums, street drains overflow during heavy rains, and water rises to mid-calf and rushes onto floors where residents sleep. Visiting several of these places, I hear one constant refrain: “We want a sewer, and we want our own toilets”—an aspirational leap over government-built latrines. But many slums are too crowded or structurally unsound for sewer lines, and the government is reluctant to provide services to residents it considers illegal, on land that may be slated for private development.

So where’s the hope? Hacking their way through thickets of interdepartmental bureaucracy, WaterAid India and the Centre for Urban and Regional Excellence, a Delhi-based nonprofit, recently raised $28,000 to install a small, shallow sewer line in one of Safeda Basti’s alleys. The pipe, which drops into a trunk line on the slum’s border, was completed in 2015. Within months 62 households installed latrines, some atop their roofs, that emptied into the new sewer—subtracting 300 people from the crowds at the toilet complex.

All of a sudden seemingly intractable cultural taboos had fallen away: It was OK to live near a toilet. The way Gupta describes it, the sanitation challenge in Indian cities is roughly the opposite of the one in the countryside. Changing behavior in the city is relatively easy; building infrastructure—and maintaining it—are hard.

View Images HAITI Outside the town of Dame-Marie, residents bathe, wash clothes, and collect drinking water in streams. But they also defecate nearby, and storms sluice waste into the water. After Hurricane Matthew hit in 2016, the area suffered a resurgence of cholera, a bacterial disease that spreads when infected feces contaminate water and food.

For Bezwada Wilson, a Delhi-based human rights activist who works to uplift Dalits, the flush toilet is the only path to social emancipation. “India has electricity and roads,” he says. “We deliver natural gas. And when it comes to drains and sewers, the government doesn’t have the money?” He shakes his head, incredulous. Even in rural areas Wilson doesn’t see the point in promoting pit latrines. “More latrines will only lead to more coerced manual cleaning,” he says.

Besides being expensive, however, flush toilets and sewers require running water, which many parts of India still don’t have. As the country develops, such amenities may become universal—but that day is surely decades away. In the meantime millions more children will have died. The question is how best to reduce that number.

Technology can help. Waterless, solar-powered toilets that are under development will sterilize the waste they collect, making it safe to use on crops or as charcoal. A cheaper, simpler solution, available now, involves composting latrines that have two pits spaced about a yard apart. After the first pit fills, waste is diverted into the second pit. Long before it fills, the contents of the first pit dry out, pathogens die, and the crumbly remains—high in nitrogen, phosphorus, and potassium—can be safely applied to farm fields.

But the pit still does have to be excavated—and that has sharply limited the spread of twin-pit latrines in India. “Villagers say, ‘No matter how dry it is, it’s still poop,’” RICE’s Srivastav says. “‘Removing it will make me untouchable. People will not want to share a hookah with me.’”

For RICE’s Diane Coffey, that prejudice is the nub of India’s problem. Teaching people that ordinary pits take years to fill, not months, is important, she says; so are affordable pumps that would make emptying pits more hygienic and less disgusting. But the most important thing India can do to stop open defecation, Coffey says, is “to confront casteist ideas that make internationally normal latrine pits unacceptable.” Emptying a latrine is never pleasant, she and Dean Spears write in their book, Where India Goes. But in other nations it’s at least not “a symbol of generations of oppression and humiliation.”

Parameswaran Iyer, India’s secretary of drinking water and sanitation, acknowledges the role that caste plays in sanitation. “But the Swachh Bharat mission is actually helping to break down barriers,” he insists, “because a village can’t become open defecation free if different sections aren’t ODF. The entire community is in it together.” Iyer turns toward a hand-numbered sign on his office wall. “You see that?” he asks. “One hundred thousand is the number of villages that are ODF today.” Just 540,000 to go, I note, three years before Modi’s deadline.

View Images HAITI It took Fritznel Xavier’s parents six hours to carry the vomiting teenager to the cholera treatment center in Jérémie. Stabilized with intravenous fluids, Fritznel survived but returned to a village that lacks adequate toilets. Cholera most frequently afflicts the young and the old. In Haiti it sickened tens of thousands in 2016.

Iyer remains undaunted. The government rewards certified ODF villages by moving them to the front of the line for road or drinking-water improvements, he says. It has launched an advertising campaign that exalts Swachh Bharat mascots, like the 106-year-old woman in Chhattisgarh state who sold seven goats to build two toilets. It has enlisted cricket and Bollywood stars to exhort people to use the new latrines. On the subject of emptying them, the ads are silent.

Meanwhile villages keen on ODF status are taking action against violators—Moolchand chasing furtive lota-carriers is just one example. In some villages, watch committees post photographs of violators on the Internet or shame them on the radio. Village leaders may even jail offenders or fine them 500 rupees—more than twice what a farmhand earns in a day—while district leaders may cut off government rations of rice, wheat, sugar, oil, or kerosene.

All these measures are beginning to have an impact, Iyer says. “Even if there are centuries of old habits and beliefs, I think they are changing a little. The momentum has picked up.”

That may be true, but critics say the government’s analysis of the remaining challenge is too rosy. Citing UN statistics, it says that the open-defecation rate declined from 75 to 44 percent of the population between 1990 and 2015. But that estimate reflects only the number of latrines that have been constructed—not the number that are actually used, consistently, by every family member.

View Images VIETNAM In the southern village of Vinh Xuyen, Phham Thi Lan washes her son with pond water beside the family latrine, which drops nutrients into their fish farm. Recycling feces this way is an old practice that’s better than open defecation and can be done safely—but separating waste from drinking and bathing water is imperative.

Early one morning in a village north of Bhopal, more than a hundred people gather in an open area, where Santoshi Tiwari, a sharp-tongued field-worker with Samarthan, a regional nonprofit, tells them to sit down, close their mouths, and listen. First she asks what they’re proudest of in their village. The temple, they say. And what gives them the most shame? The human waste along the roads.

Like a Pied Piper, Tiwari then leads the villagers past their temple and into a recently plowed field, where she suddenly halts. “What is this?” she demands, pointing toward the ground.

A few wags offer variants on the technical term. Tiwari asks if the excrement can be identified—by man, woman, child, or caste. “It’s from the lower caste,” a woman says, “because this is a lower caste area.” Tiwari moves on: How many people live here? About 1,500, a young man shouts. Tiwari explains that each person daily produces more than half a pound of feces, which means the village annually produces around 300,000 pounds. The crowd murmurs, and Tiwari leads them in a round of mocking applause.

Now she turns serious. She explains how feces circulate through the village on the legs of flies, in water, and in dust. She opens a bottle of water, pours some into a plastic cup, and sips. Then she plucks a long hair from her head, draws it through the pile at her feet, and swirls the filthy strand in her water cup. The crowd steps backward; their faces contort with disgust. “Would you drink this water?” Tiwari asks, proffering the cup. “This is just one hair,” she adds. “Flies have six legs.”

View Images VIETNAM Indoor plumbing in newer schools has helped whittle Vietnam’s open-defecation rate from 39 percent in 1990 to almost zero today. Even young students, like this five-year-old in Ben Tre city, act as sanitation ambassadors, bringing home lessons on toilet use and handwashing to share with their families.

Triggering disgust—by mapping and quantifying feces and dipping tainted hairs in drinking water—is the hallmark of “community-led total sanitation,” an approach that has been credited with reducing open defecation in places not plagued by caste division. Today’s gathering is an opening salvo: Sensing commitment, Tiwari promises to return to help residents navigate the paperwork for the government subsidy, purchase bricks, and train masons to build pits. Settling who will empty them is beyond her brief, as is what happens to the sludge—a long-standing problem India scarcely has begun to address. But even if the sludge is merely dumped in some far-off ditch, it poses less of a health threat than individual piles of feces on nearby roads and fields.

Samarthan and other aid groups promote twin-pit latrines and the harmless fertilizer they yield. After Tiwari’s presentation I ask a village elder, a non-Dalit, what he’d do after his pit was full. “It will be like mud, so we’ll have no problem emptying it ourselves,” he says. I want to believe him. But many others, in supposedly ODF villages, have told me they’ll call a Dalit.

Back in the center of the village, Tiwari reminds her audience of the link between feces and diarrheal illness and calculates that the village spends tens of thousands of rupees a year on medicine. “You are enriching the doctors,” she squawks. “Imagine how you could improve your house or your roads with that money.” Tiwari appeals to their dignity. She shames them for spending rupees on mobile phones, or a thousand kinds of funeral foods, instead of on toilets.

She tries every argument. Then, after an hour-long harangue, Tiwari asks, “Should this change?” “Yes!” the crowd shouts. “Who will end open defecation?” she screams. A hundred hands shoot skyward.