<Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> <P> A customs union is a type of trade bloc which is composed of a free trade area with a common external tariff . The participant countries set up common external trade policy, but in some cases they use different import quotas . Common competition policy is also helpful to avoid competition deficiency . </P> <P> Purposes for establishing a customs union normally include increasing economic efficiency and establishing closer political and cultural ties between the member countries . </P> <P> It is the third stage of economic integration . </P>

What was the purpose of a customs union