Any housing authority created under chapter 25 or 26 of this title, and any redevelopment agency created under chapter 31 of this title, is authorized to make loans as provided in this chapter to any one or more persons, partnerships, or corporations for the purpose of financing the acquisition, construction, rehabilitation, or other development of one or more lower income housing projects located within their respective communities. For purposes of this chapter, a lower income housing project means one or more buildings and structures, and all real and personal property associated therewith, to be used primarily for residential rental purposes; provided, that not less than twenty percent (20%) of the residential units in the project will be occupied or available for occupancy, for a term of years that the authority or agency determines, by persons or families whose income is fifty percent (50%) or less of the median gross income for the area in which the project is located, as determined by the United States Department of Housing and Urban Development; and provided, further, that a portion of the cost of the project has been approved prior to April 30, 1988 for funding by a housing development grant under § 17 of the United States Housing Act of 1937 [42 U.S.C. § 1417, repealed by Pub. L. 90-448, Aug. 1, 1968].