She grew up in a dusty West Bengal village, where no one had access to toilets. Most of the female villagers headed to a particular field. But it was a bit of a walk and often required asking another woman to help shield you from lecherous men.

Boko, a 35-year-old woman with a yellow sari and a big smile, now sweeps floors at a truck stop with toilets. It’s a big improvement, says the woman, who identified herself only by her first name.

A United Nations report released March 15 says that despite progress in the last two decades, 2.4 billion people around the world still lack access to basic sanitary facilities -- including an estimated 638 million in India alone.

Lacking access to a toilet, something most people in the developed world don’t think about, involves more than just embarrassment and inconvenience. It’s also a significant health hazard. Globally, about 1.5 million children die each year as a result of a lack of water, sanitation and hygiene, according to UNICEF, the U.N. children’s agency.

“We go to the toilet on the street,” said Basarat Ansari, 30, a homeless laborer working in a ritzy Kolkata neighborhood. “I know other people have to walk in it. But you don’t have much choice if you have to go.”

Women often have a harder time.

Chandana Das, 40, sat cooking a curry on a Kolkata street where she has lived for years. Nearby, a string of men used a green tiled urinal in open view.

“Men can go over there, but we can’t very well do that,” Das said. “I’ll walk several blocks to a toilet at the market. You have to pay, but what can you do?”

Up to 10% of Kolkata’s population lives on the street or in shantytowns -- including rickshaw pullers, migrants from neighboring states and illegal immigrants from Bangladesh. That means many people end up sleeping near where someone else has defecated a few hours earlier.

An estimated three dozen civic groups and neighborhood committees offer public toilets -- only enough so that there are about two per square mile in a teeming city of 15 million.

One such group, Sulabh International, operates 7,500 toilets across the country, in nearly every Indian state, and employs 50,000 people. But founder Bindeshwar Pathak said Sulabh’s effort is “just like a peanut,” compared with India’s needs, which he estimates at 1 million public toilets and 120 million household toilets.

Though the problem in cities is often more acute, globally 70% of those without toilets live in rural areas.

In India, parents often won’t allow their daughters who have reached puberty to attend rural schools that lack toilets, fearing they will be molested, which would ruin their chances of attracting a suitor. That makes toilets a linchpin in efforts to improve women’s status.

Some blame the state for the dearth of public facilities.

“If officials spent even 10% of our tax money where they should, we’d be a far more developed country,” said Gourav Ghosh, 24, a hotel developer in Kolkata, formerly known as Calcutta. “But it seeps away from corruption. Before an election, the toilets are maintained. Afterwards, it’s back to usual -- filth and disrepair. Inevitably, it’s poor people who suffer.”

Others blame a lack of civic pride. It’s not unusual to see men, including well-dressed businessmen, urinating on a wall just beside a public toilet to avoid the smell and filth inside.

New Delhi has vowed to clean up in time for the Commonwealth Games it is hosting this fall. City officials are encouraging companies to build 250 new toilet facilities-- “fully air-conditioned, with flowerpots and large mirrors” -- around the capital.

“We are all set to usher in a toilet revolution in the city,” Amiya Chandra, head of the city department handling the project, told the media at the launch.

The city has suggested that restaurant companies fund construction in order to attract customers into adjoining eateries or, as news website Mid-Day.com explained: “Have a full meal inside without pinching your nose.”

Chandra said the project promised to lend an artistic flair to India’s capital.

“Presently, the city of Delhi resembles a stinking toilet,” he said, “but we are trying hard to make toilets an aesthetic experience.”

mark.magnier@latimes.com