31 C.F.R. § 515.591
Persons subject to the jurisdiction of the United States are authorized to provide to Cuba or Cuban nationals services related to developing, repairing, maintaining, and enhancing Cuban infrastructure that directly benefit the Cuban people, provided that those services are consistent with the export or reexport licensing policy of the Department of Commerce. For the purposes of this section, infrastructure means systems and assets used to provide the Cuban people with goods and services produced or provided by the public transportation, water management, waste management, non-nuclear electricity generation, and electricity distribution sectors, as well as hospitals, public housing, and primary and secondary schools. This authorization includes projects related to the environmental protection of U.S., Cuban, and international air quality, waters, and coastlines.
Note 1 to § 515.591 : For provisions related to transactions ordinarily incident to the exportation or reexportation of items to Cuba, see §§ 515.533 and 515.559 . See § 746.2(b) of the Export Administration Regulations (15 CFR parts 730 through 774) for the Department of Commerce's Cuba licensing policy.
Note 2 to § 515.591 : See § 515.564 for a general license authorizing travel-related and other transactions incident to professional research and professional meetings in Cuba, § 515.533(c) for a general license authorizing travel-related and other transactions relating to certain exports and reexports to Cuba, and § 515.575(a) for a general license authorizing transactions, including travel-related transactions, related to certain humanitarian projects.
31 C.F.R. §515.591