A/RES/58/222 the proportion of people who do not have access to basic sanitation, as reaffirmed in the Johannesburg Plan of Implementation; 25. Recognizes that the lack of adequate housing remains a pressing challenge in the fight to eradicate extreme poverty, particularly in the urban areas in developing countries, expresses its concern at the rapid growth in the number of slum dwellers in the urban areas of developing countries, particularly in Africa, stresses that, unless urgent and effective measures and actions are taken at the national and international levels, the number of slum dwellers, who constitute one third of the world’s urban population, will continue to increase, and emphasizes the need for increased efforts, with a view to significantly improving the lives of at least 100 million slum dwellers by 2020; Specific initiatives in the fight against poverty 26. Also recognizes the important potential contribution of the World Solidarity Fund to the achievement of the Millennium Development Goals, in particular the objective to halve, by 2015, the proportion of people living on less than one dollar a day and the proportion of the people who suffer from hunger; 27. Reiterates its endorsement of the decision of the World Summit on Sustainable Development to establish the World Solidarity Fund to eradicate poverty and to promote social and human development in the developing countries, while stressing the voluntary nature of the contributions and the need to avoid duplication of existing United Nations funds and encouraging the role of the private sector and individual citizens relative to Governments in funding the endeavours, as set out in the Johannesburg Plan of Implementation; 28. Encourages Member States, international organizations, the private sector, relevant institutions, foundations and individuals to contribute to the World Solidarity Fund; 29. Requests the Administrator of the United Nations Development Programme, in that regard, to take further measures to operationalize the World Solidarity Fund by establishing, on an urgent basis, the high-level committee whose task it is to define the strategy of the Fund and to mobilize resources to enable it to start its activities in the field of poverty alleviation; 30. Acknowledges the significance of greater involvement of developing countries in joint efforts, including those among developing countries, to overcome extreme poverty, and in this context takes note of the initiatives undertaken by the developing countries, including those announced at the fifty-eighth session of the General Assembly; 31. Welcomes the initiatives undertaken by regional and subregional organizations for overcoming extreme poverty; Africa, least developed countries, landlocked developing countries and small island developing States 32. Stresses the importance, as recognized in the Millennium Declaration, of meeting the special needs of Africa, where poverty remains a major challenge and where most countries have not benefited fully from the opportunities of globalization, which has further exacerbated the continent’s marginalization; 6