Cities of the first and second class are hereby authorized to incur or to increase their indebtedness by the issue and sale of obligations of the city, in the manner and subject to the limitations provided by law, for the purpose of assisting in the improving, constructing, reconstructing or resurfacing any of the streets, or sections thereof, the improvement of which is authorized in accordance with the provisions of this subdivision of this article.
36 P.S. § 670-549