The world’s rapidly increasing slums are becoming a social “time bomb” ready to explode, a United Nations report suggests. Despite the efforts of member nations, the number of persons living in slums increased from 776.7 million in 2000 to some 827.6 million in 2010.

“Short of drastic action,” the latest UN Habitat report says, “the world slum population will probably grow by six million each year (or another 61 million people) to hit a total of 889 million by 2020.”

Even though slum growth in China and India has slowed, the overall world problem is dramatically increasing.

While rapid urbanization, and economic and climate changes are all contributing factors, The Washington Post reported that one “alarming trend highlighted by the report is that of ‘refugee cities’—mostly the result of war and violent conflict.”

Developing nations house 70 percent of the total refugee population. In Amman, Jordan, one in four inhabitants are displaced persons.

Conditions are especially dire in sub-Saharan Africa and South Asia, as impoverished people are often driven off their farmland into metropolitan areas. In many cases, slum dwellers are forced into poorly built high-rise apartments, thereby freeing up urban areas for condominiums and commercial construction. This often leads to overcrowding and inhumane living conditions, which in turn have caused a steep increase in diabetes, obesity and HIV infections among slum dwellers.