At the same time, 15 countries focused on negotiating a simple trade agreement. They agreed to remove trade restrictions on $10 billion or one-fifth of the world`s trade zone. A total of 23 countries signed the GATT agreement on 30 October 1947, paving the way for its implementation on 30 June 1948. Derogations under Article XX of the GATT are permitted as long as the resulting measures are not unjustified or arbitrary. This implies that the country has no other means of pursuing objectives that would avoid restrictive trade practices. In this context, the general principles of international law and other international conventions ratified by members may also be taken into account when interpreting the extension of a waiver (US – Shrimp, WTAB/R, 1998, para. 35). See also the Vienna Convention on Treaty Law Article 31.3.c). Most nations have adopted the nation`s most preferred principle when setting tariffs, which has largely replaced quotas. Tariffs (preferably quotas, but still an obstacle to trade) have in turn been constantly reduced in successive rounds of negotiations. The SPS agreement has changed the way trade decisions are made with respect to agricultural products. Its main intention is to facilitate trade and avoid the use of sanitary and plant health measures as unjustified barriers to trade.
The agreement stipulates that all measures must be scientifically sound and should not be unnecessarily restrictive, while recognizing the right of countries to the protection of human, animal or plant life or health. 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). Progress in the negotiations stalled after negotiations broke down in July 2008.   The Kennedy Round took place from 1962 to 1967.