Rate orders of State agencies
The district courts shall not enjoin, suspend or restrain the operation of, or compliance with, any order affecting rates chargeable by a public utility and made by a State administrative agency or a rate-making body of a State political subdivision, where:
Jurisdiction is based solely on diversity of citizenship or repugnance of the order to the Federal Constitution; and,
The order does not interfere with interstate commerce; and,
The order has been made after reasonable notice and hearing; and,
A plain, speedy and efficient remedy may be had in the courts of such State.
(June 25, 1948, ch. 646, 62 Stat. 932.)