This is the VOA Special English Development Report.

Fifty years ago, most people lived in rural areas.  But the world has changed.  By some point next year, more than half of all people will live in cities, for the first time in history.  So says the most recent estimate from the United Nations. 

A slum in Haiti's capital, Port-au-Prince

City life is not always a bad thing, but many experts worry about this process of urbanization.  A new report from the Worldwatch Institute says it is having a huge effect on human health and the quality of the environment.  The environmental research group in Washington released its two thousand seven "State of the World" report last week. 

Of the three billion people who live in cities now, the report says, about one billion live in unplanned settlements.  These are areas of poverty, slums, that generally lack basic services like clean water, or even permanent housing. 

The report says more than sixty million people are added to cities and surrounding areas each year, mostly in slums in developing countries.

Molly O'Meara Sheehan led the Worldwatch report.  She says the international community has been too slow to recognize the growth of urban poverty.  Policymakers, she says, need to increase investments in education, health care and other areas.

The report talks about some successful efforts by local governments and community groups.  For example, it says Freetown, Sierra Leone, has established farming within the city limits to meet much of its growing food demands.  In Colombia, engineers have created a bus system in Bogota that the report says has helped reduce air pollution and improve quality of life.

Olav Kjorven heads the Environment and Energy Group at the United Nations Development Program.  He agrees that the link between urban poverty and the environment is serious.  But he says governments also need to consider why people are moving out of rural areas.  Climate change, drought, floods -- there are many reasons forcing people to leave, he says.

Olav Kjorven says the two issues of poverty reduction and the environment have existed side by side, but rarely have they connected -- until now.  He says governments are starting to understand that environmental collapse is not a natural cost of economic development.  Instead, he says, it is hurting the possibility for growth.

And that's the VOA Special English Development Report, written by Jill Moss.  You can learn more about development issues at voaspecialenglish.com.