NAIROBI — Beatrice Oriyo laughed out loud when asked if there was a playground where her three children could play near her home in Kibera, Nairobi’s biggest informal settlement.

“There’s nothing like that here,” the 34-year-old Ms. Oriyo told the Thomson Reuters Foundation by phone from the one-roomed corrugated iron home that she rents for 6,000 Kenyan Shillings ($43.18) a month.

“We don’t even have our own toilet — we have to pay each time to use the public toilets. We bathe in the same room that is our kitchen, living room and bedroom. The idea of a playground here is like a joke,” she said.

More than one billion people globally reside in overcrowded urban slums such as Kibera, where they live a precarious existence, struggling to access basic amenities such as adequate housing, water, sanitation, power and waste collection, said the United Nations’ agency for urban development, UN-Habitat.

This figure is projected to reach three billion people by 2050 — as populations grow and more people migrate to cities in search of better opportunities — presenting a major challenge for many governments across the world.

UN-Habitat forecasts that 50% of this growth in slum populations will be concentrated in eight countries: Nigeria, the Philippines, Ethiopia, Tanzania, India, the Democratic Republic of Congo, Egypt and Pakistan.

“Our future is urban,” UN-Habitat Executive Director Maimunah Mohd Sharif told reporters on the sidelines of the UN-Habitat Assembly, a five-day conference bringing together ministers, senior officials and civil society groups to strengthen commitments to develop more sustainable cities.

“More than half of the world’s population lives in cities and towns. That population is going to increase to 70% by 2050. So, tackling urban poverty and inequality is more urgent than ever before,” she said.

More than half of Kenya’s urban population lives in unplanned overcrowded settlements like Kibera, the World Bank says. The warren of narrow dirt-paved alleys is home to at least 250,000 people — most living cheek-by-jowl in windowless one-room shacks.

Most residents are migrants from rural areas and earn less than $2 a day in low-income jobs as motorbike taxi drivers, security guards, domestic workers or casual laborers. They are unable to afford decent housing in Nairobi.

Toilets are shared pit latrines which often overflow during the rainy season, there is little piped water so residents rely on expensive and irregular private water tankers to fill their buckets and containers daily.

Poor drainage and garbage collection mean floods are common — not only destroying homes and possessions, but also contaminating drinking water and even causing deaths through building collapses, electrocution and drowning.

With high levels of poverty and youth unemployment, crimes such as mugging, robbery and sexual violence against women are rife.

Residents in informal settlements are also at risk of forced evictions by authorities, and instances of bulldozers moving in to demolish people’s homes are common.

“It’s not easy to live here,” Mercy Achieng, a 41-year-old single mother, who earns 500 shillings weekly washing laundry, said by phone from Kibera, only a 30-minute drive from the scenic 140-acre manicured grounds of UN conference in a green, upmarket part of the capital.

“It is a good community and we all know and help one another, but there is no privacy, no safety and no security. The landlord can kick us out, or the bulldozers can come.”

UN-Habitat officials said that while lack of housing was previously seen as a problem faced by developing countries, it had become a global crisis with many rich countries such as the United States, Britain and Germany all facing shortages.

“The global housing crisis is present in all world regions today,” said Edlam Yemeru, head of the Knowledge and Innovation Branch of UN-Habitat.

“Although the manifestations differ, almost all countries are grappling with the urgency to ensure that their citizens have access to adequate housing.”

Data from the Organisation for Economic Co-operation and Development shows that costs of housing have risen faster than earnings and inflation in many member states in recent years.

Kenyan President William Ruto, who came to power last year, has made affordable housing a centerpiece of his government’s development agenda and announced plans to construct 250,000 houses annually for low income-earners, including those in informal settlements like Kibera.

“Realizing that more than half of Kenya’s population will live in urban areas by 2050, we have integrated universal housing as a critical pillar of the national bottom-up economic transformation agenda,” Mr. Ruto told delegates at the UN-Habitat Assembly on Monday last week.

He said this would include green buildings, green spaces, adoption of low carbon energy, including low carbon transport solutions, as well as urban agriculture and effective waste management.

But the financing of the affordable housing program — which would impose a 3% levy on employee salaries with employers contributing the same amount — has been heavily criticized by the opposition and sparked protests by labor unions.

Joseph Muturi, chair of Slum Dwellers International — a network of the urban poor from more than 18 countries — said governments needed to focus on upgrading slums, rather than relocating slum dwellers to housing projects outside cities.

Previous examples of moving families from slums to poorly serviced new housing schemes on the fringes of cities had left them isolated with few job options and forcing them to eventually move back to the slums, he said.

“You can’t relocate slum dwellers far from the cities. They have the right to participate as citizens of these cities just like everyone else,” said Mr. Muturi.

“When you relocate people, you are also killing the social fabric that these communities have woven over decades — the best solution is in-situ upgrading of slums. You have to engage with slum dwellers, provide secure tenure and the amenities they need.” — Thomson Reuters Foundation