Duties are tributes that are placed on goods or other resources with the intention of creating an artificial barrier to the freedom to commercialize the resource affected by the duty. Customs duties indicate a particular type of indirect tax applied to the value of all products imported (import duties) or exported (export duties) or transiting through the territory (transit duties) of a country. The duty is imposed either on a specific measure (weight, length, surface area number of the goods) or ad valorem (the value of the goods).
Duties can be fiscal, to increase state revenue, or protective, to reduce imports of a good or protect a particular industry.
Through the imposition of tariffs between countries, it is possible to arrive at the so-called trade war which consists of an instrument of a more general trade war among the countries that have levied these taxes on goods.