§ 450. Policy and purposes of article. It is hereby declared that there exists in municipalities in this state a seriously inadequate supply of safe and sanitary dwelling accommodations; that such shortage constitutes an emergency and a grave menace to the health, safety, morals, welfare and comfort of citizens of this state; that existing conditions of deterioration of housing marked by noncompliance with the multiple dwelling law or local housing codes threaten a further decrease in such supply; that rehabilitation and improvement of dwellings to prolong the useful life of such dwellings may be necessary to arrest such conditions of deterioration; that the elimination of such conditions by rehabilitation or other improvement cannot readily be provided by the ordinary unaided operation of private enterprise without public aid in the form of low interest loans or grants to owners of such multiple dwellings; that such rehabilitation or other improvement of such dwellings to bring them into conformance with the multiple dwelling law and local housing codes is a public use, a public purpose and a city purpose for which public money may be loaned or granted by a municipality and for which indebtedness may be contracted by a municipality; that such conditions require the provisions hereinafter enacted, and the necessity in the public interest for the provisions hereinafter enacted is hereby declared as a matter of legislative determination.