The term “housing project” whenever used in this Article shall mean any undertaking (i) to demolish, clear, remove, alter or repair unsafe or insanitary housing and/or (ii) to provide dwelling accommodations for persons of low income, and said term may also include such buildings and equipment for recreational or social assemblies for educational, health or welfare purposes, and such necessary utilities as are designed primarily for the benefit and use? of the occupants of such dwelling accommodations. (1935, c. 409, s. 2.)