The Secretary is authorized to provide fellowships for the graduate training of professional city planning, management, and housing specialists, and other persons who wish to develop a general capacity in urban affairs and problems as herein provided. Persons shall be selected for such fellowships solely on the basis of ability and upon the recommendation of the Urban Studies Fellowship Advisory Board established pursuant to subsection (b). Fellowships shall be solely for training in public and private nonprofit institutions of higher education having programs of graduate study in the field of city planning or in related fields (including architecture, civil engineering, economics, municipal finance, public administration, urban affairs, and sociology) which programs are oriented to training for careers in city and regional planning, housing, urban renewal, and community development.