Amending an Ordinance approved December 15, 1969, as amended, which approved the redevelopment proposal, the urban renewal plan and the relocation plan of the Redevelopment Authority of the City of Philadelphia for the redevelopment of the Model Cities Urban Renewal Area, by approving the twenty-eighth amendment of the redevelopment proposal, the twentieth amendment to the urban renewal plan and the nineteenth amendment to the relocation plan, which provide, inter alia, for the expansion of the northern boundary from York street to Cumberland street between Fourth street and Front street, the — Open Common Ground