During the first World War certain industries like explosive producing factories, war ship building and other engineering works expanded in order to meet wartime requirements. However, when the war came to an end, these industries had to be abandoned or modified. Employees were sacked in huge numbers and stocks got dissolved. The war had placed a heavy burden of debt on every European country. This affected the working class. The humongous fine imposed by the Treaty of Versailles on Germany created hyperinflation. This eventually contributed to economic instability and reduced industrial output worldwide.
Thus, a new wave of economic nationalism developed where each country tried to protect its own economy.