Slums were common in the 18th to early 20th centuries in the United States and Europe. More recently, slums have been predominantly found in urban regions of developing and undeveloped parts of the world, but are also found in developed economies.
According to UN-Habitat, around 33% of the urban population in the developing world in 2012, or about 863 million people, lived in slums. The proportion of urban population living in slums was highest in Sub-Saharan Africa (61.7%), followed by South Asia (35%), Southeast Asia (31%), East Asia (28.2%), West Asia (24.6%), Oceania (24.1%), Latin America and the Caribbean (23.5%), and North Africa (13.3%). Among individual countries, the proportion of urban residents living in slum areas in 2009 was highest in the Central African Republic (95.9%). Between 1990 and 2010 the percentage of people living in slums dropped, even as the total urban population increased. The world's largest slum city is found in the Neza-Chalco-Ixtapaluca area, located in the State of Mexico.
Slums form and grow in many different parts of the world for many different reasons. Some causes include rapid rural-to-urban migration, economic stagnation and depression, high unemployment, poverty, informal economy, poor planning, politics, natural disasters and social conflicts. Strategies tried to reduce and transform slums in different countries, with varying degrees of success, include a combination of slum removal, slum relocation, slum upgrading, urban planning with citywide infrastructure development, and public housing
Slum settlements are characterized by piles of suffocating rubbish and stagnant waters that form the breeding grounds for rodents, flies, mosquitoes and other harmful insects that transmit diseases to man.
Slum squatters have no regard for environmental protection and their daily activities make such settlements hazardous to human inhabitation.
Now the question is: where do we place Freetown based on this definition?