Rapid urbanization is occurring in cities in LEDCs due to rural-urban migration driven by push and pull factors. This results in several problems including overcrowded slums/shanty towns with poor infrastructure, high unemployment, and environmental issues. In Rio de Janeiro, rapid population growth from natural increase and migration has contributed to housing shortages, inadequate employment, and sanitation problems. Solutions implemented in favelas like Rocinha include self-help housing schemes providing materials for residents to upgrade dwellings and improving basic services.