The 1973 Oil Crisis began in earnest on October 17, 1973, when the members of Organization of Arab Petroleum Exporting Countries (OAPEC, consisting of the Arab members of OPEC plus Egypt and Syria) announced, as a result of the ongoing Yom Kippur War, that they would no longer ship petroleum to nations that had supported Israel in its conflict with Syria and Egypt (i.e., to the United States, its allies in Western Europe, and to Japan).
About the same time, OPEC members agreed to use their leverage over the world price-setting mechanism for oil in order to raise world oil prices, after attempts at negotiation with the "Seven Sisters" earlier in the month failed miserably. Due to the dependence of the industrialized world on crude oil, and the predominant role of OPEC as a global supplier, these price increases were dramatically inflationary to the economies of the targeted countries, while at the same time suppressive of economic activity. The targeted countries responded with a wide variety of new, and mostly permanent, initiatives to contain their further dependency.