Area pricing policy

What does Area pricing policy mean in American Law?

The definition of Area pricing policy in the law of the United States, as defined by the lexicographer Arthur Leff in his legal dictionary is:

A policy of the Federal Power Commission providing that proposed natural gas rates were to be approved on the basis of prices determined for various producing areas. The policy was massively litigated by the affected parties, but was finally largely upheld by the Supreme Court in 1968.