Most nations have adopted the principle of MFN when setting tariffs, which have largely replaced quotas. Tariffs – which are preferable to quotas, but which are still an obstacle to trade – have again been constantly reduced in successive rounds of negotiations. THE GATT and its successor, the WTO, have succeeded in reducing tariffs. Average tariff levels for large GATT participants were about 22% in 1947, but were 5% after the Uruguay Round of 1999.  Experts attribute some of these tariff changes to the GATT and the WTO.    Average fee rates for large GATT participants were about 22% in 1947.  As a result of the first rounds of negotiations, tariffs at the heart of the GATT of the United States, the United Kingdom, Canada and Australia have been reduced relative to other contracting and non-GATT countries.  During the Kennedy Round (1962-67), the average level of tariffs for GATT participants was about 15%.  After the Uruguay Round, tariffs were less than 5%.
The third round took place in 1951 in Torquay, England.   38 countries participated in the cycle. 8,700 tariff concessions were granted for the remaining tariff on three-fourth of the tariffs that came into effect in 1948. The simultaneous rejection of the Havana Charter by the United States meant the creation of the GATT as a global federation.  The General Agreement on Tariffs and Trade (GATT), signed on 30 October 1947 by 23 countries, was a legal agreement to minimize barriers to international trade by removing or reducing quotas, tariffs and subsidies, while maintaining important rules. The GATT is expected to stimulate economic recovery after the Second World War through the reconstruction and liberalization of world trade. The Doha Development Round began in 2001. The Doha Round began in 2001 with a ministerial meeting in Doha, Qatar. The aim was to focus on the needs of developing countries. The main factors examined are trade facilitation, services, rules of origin and dispute resolution. Special and differentiated treatment of developing countries was also discussed as a principal. The following ministerial meetings were held in Cancer, Mexico, in 2003 and Hong Kong (2005).
These negotiations took place in Paris, France (2005), Potsdam, Germany (2007) and Geneva, Switzerland (2004, 2006, 2008).