JIM LEHRER: Finally tonight: the population boom in the world's poorest urban areas. Our report comes from a GlobalPost series about the growth of the so-called megacities. It centers on Dhaka, capital of the South Asian nation Bangladesh.
This story was prepared by the team of Erik German and Solana Pyne.
SOLANA PYNE, GlobalPost: This is a good day for 4-year-old Shahadat. When he complained of hunger, his father had a piece of fruit to give him.
ABDUR RAHIM, Bangladesh (through translator): When he tells me he's hungry, I try to bring him food after work. If I can't buy any food, he has to live with the hunger.
SOLANA PYNE: Abdur Rahim's struggle to feed his family began three years ago. That's when one of South Asia's biggest rivers, the Brahmaputra, washed away the land his family had farmed for generations.
ABDUR RAHIM (through translator): My land was over there. Now it's water. It's a river.
SOLANA PYNE: He now drives a rented rickshaw in a town across from his former home and earns about a dollar a day. Barely able to afford the rent for this windowless, mud-floored shack, he's decided to move his family to Dhaka, the country's capital.
He and his wife, Shapla, say they will borrow the $10 they need for the trip and catch a bus within the week, joining a wave of some 400,000 migrants who move to Dhaka every year.
SHAPLA RAHIM, Bangladesh (through translator): I feel terrible, but we have to leave everyone we know, all our relatives and neighbors, and take our kids to an alien place.
SOLANA PYNE: The city they're moving to is growing so fast, each new census is quickly outdated. But local experts estimate it's now home to 15 million people. Dhaka is perched on the leading edge of a global trend. For the first time in human history, the world has become more urban than rural. By mid-century, some 80 percent of the Earth's population will live in cities, many of them in the exploding slums of the developing world. For good or ill, Dhaka is setting an example.
ATIQ RAHMAN, Bangladesh Centre For Advanced Studies: You are seeing the early future of the world, which is not a very pleasant thought at this point in time. Half of the population of the developing world will be in the urban centers within the next decade.
SOLANA PYNE: If you want to know what that might look like, Dhaka is among the best places to visit. The World Bank called it the fastest growing of the world's 20 or so megacities, urban areas with populations over 10 million. It's also one of the poorest. Vast slums dot every neighborhood and house at least a third of its people. In less than 15 years, the United Nations predicts Dhaka's population will surpass that of Shanghai, Mexico City, or New York.
REHMAN SOBHAN, Centre For Policy Dialogue: Well, I think, if you simply project the present into the future, then, obviously, we are headed no good place.
SOLANA PYNE: At the end of British rule in 1947, Dhaka had just 250,000 residents. Two-and-a-half decades later, when Bangladesh won independence from Pakistan, the city had nearly 1.7 million.
Since then, rural poverty and frequent natural disasters have pushed Bangladeshis to Dhaka at breakneck speed. Each new decade has seen the city's population double. Everywhere, you can see the damage wrought by this frenzied growth. By one rough estimate, traffic alone costs the city $2 billion a year.
ATIQ RAHMAN: I have adopted what I call car meeting. I take my colleagues with me in a car, with a computer, and we talk and we hold our meeting in the car over the two hours.
SOLANA PYNE: Raw sewage flows into lakes and rivers so polluted they're beyond treatment. Electricity and water networks strain to cope with surging demand. Protests erupt periodically when routine water shortages last more than a few days.
KHONDAKER AZHARUL HAQ, former director, Dhaka Water Authority: Believe me, a serious water crisis in the city can bring down a government. That kind of magnitude, water has acquired.
SOLANA PYNE: The new arrivals are often the hardest hit, because most settle in slums. They have no title to the land they live on and can't get legal water or electricity. So, they pay two, three even four times official rates for pirated, unreliable connections.
SABINA FAIZ RASHID, BRAC University School of Public Health: If I'm a slum dweller, you know, I don't have access to basic services. I don't even have access to basic rights, because, remember, by definition, I'm illegally residing where I'm residing.
SOLANA PYNE: But new migrants keep pouring in. Some belong to Bangladesh's growing middle and upper classes, who settle in the city's upscale neighborhoods. There, one-family villas are quickly being transformed into apartment complexes.
Yet, even those who end up in slums say moving to the city still offers the best chance for a better life. After moving to Dhaka three years ago, Mahmuda Akhter found work in this garment factory. She now makes $36 a month ironing shirts, but hopes to be promoted to operating a sewing machine, which pays just over $40.
MAHMUDA AKHTER, Bangladesh (through translator): Before, I couldn't eat meat once a week, not even once a month. Now I can afford meat every week. I can buy good fish, big fish. I can afford all kinds of food. Before, it was difficult to buy a dress even once a year. Now I can afford a dress every month.
SOLANA PYNE: In the popular imagination, Third World slums have been portrayed either as ladders for escaping poverty or traps where the poor get stuck. In reality, both are true. But those who climb out are quickly replaced by new migrants.
REHMAN SOBHAN: What is going to be the most scary part of this is the two worlds which in fact have been exploding side by side. The one is the world of the high-rise buildings being recreated for a small urban elite, and then there is the world of the slums.
SOLANA PYNE: Those we spoke with in Bangladesh said the question is not whether slums in a booming megacity like Dhaka should exist. They're the fastest-growing part of this sprawling metropolis. And they herald Earth's future. Unplanned, hand-built, slum-packed cities are here, and many more are coming.
The real question a city like Dhaka can help answer is what concrete steps can make them decent places to live.
SABINA FAIZ RASHID: The government, I think, still continues to bury its head in the sand. Somehow, if you bury your head in the sand, they will just go away. It doesn't work like that.
SOLANA PYNE: One deceptively simple suggestion, put control over vital services in the hands of a single municipal government, accountable to the people it serves. As in many unplanned cities of its size, Dhaka's police, utilities and roadways are controlled by a dozen or more national authorities, mostly run by political appointees.
REHMAN SOBHAN: If you, in fact, challenge the mayor that he is not doing his job, he will say that: I cannot look after law enforcement in the city. I cannot even control the traffic.
SOLANA PYNE: Some NGOs have tried to fill the gaps, for example, finding ways to secure legal water connections for slum residents. But their successes are small-scale.
SABINA FAIZ RASHID: But I want the government to give political commitment. What has worked? What can we take forward that works well?
SOLANA PYNE: With an estimated one million people a week moving from their rural homes into cities across the developing world, those lessons are relevant far beyond Dhaka's chaotic roads and crowded waterways.
ATIQ RAHMAN: Anything that we can make work in Dhaka, probably, we could make work in almost any other city. But the challenge is enormous. It's a dynamic system. Before you have sorted one, you know, the problem becomes bigger and bigger by the day.
SOLANA PYNE: As do the slums, whose residents, day by day, night by night, are rebuilding the urban world.
GWEN IFILL: GlobalPost has four more stories from Dhaka online, among them, a look at the lives of women who work in the city's garment factories. You can find a link to GlobalPost's Web site on ours at NewsHour.PBS.org.