It is hereby declared that it is necessary in the public interest to make provision for housing families of low income and to provide for the elimination of congested and unsanitary housing conditions which exist in certain areas of the State and which are a menace to the health, safety, morals, welfare and reasonable comfort of the citizens of the State. The providing of such housing for families of low incomes and the correction of these conditions in such areas being now otherwise impossible, it is essential that provision be made for the investment of private funds at low interest rates, the acquisition at fair prices of adequate parcels of land, the construction of new housing facilities under public supervision in accord with proper standards of sanitation and safety and at a cost which will permit monthly rentals which wage earners can afford to pay and for the gradual demolition of existing unsanitary and unsafe housing. Therefore, the agencies and instrumentalities herein established are declared to be the agencies and instrumentalities of the State for the purpose of attaining the ends herein recited and their necessity in the public interest is hereby declared as a matter of legislative determination.