Urban deprivation is a major problem in cities in LEDCs, as up to 50% of residents live in substandard housing or shantytowns. Many governments have attempted solutions with varying degrees of success, such as clearing shantytowns and building high-rise apartments, upgrading existing slums to provide basic services, and constructing new "site and services" housing schemes on the outskirts of cities. However, the most successful projects have involved self-help upgrading schemes that improve conditions while allowing residents to remain in their communities.