The following information comes from scholarly literature using the ABI Inform via ProQuest database. I also spent a couple hours perusing the WTO website. It should be understood that there is no "top 10" type list of trade barriers. The WTO has 149 member countries and it's probable that every one of those countries has it's own top 10 trade peeves and none of them are likely to be exactly the same. I hope that the list below will help, even though it's not a nice, clean list of 6.
Tariffs: though these are considered trade barriers by the WTO, they are the least prohibitive and the preferred form of trade barrier. WTO wants to replace all non-tarrif barriers with tarrifs and then eventually minimize or eliminate the tariffs.
Non-Tariff Barriers:
In no particular order, these are barriers that I culled from the articles listed below.
4 broad classes of Non-Tariff Barriers:
-territoriality principle-barriers put in place because of reasons of public health or the environment within the country taking the measure
-'extraterritorial' measures-barriers implemented with the sole objective of 'convincing' or coercing a foreign government to change its policy in a given sector
-barriers raised because of environmental concerns outside the country taking the measure, but where a link with the country's territory can be established
-universal jurisdiction-no obvious territorial link with the country imposing the trade barrier, but where the measure would be considered necessary to address an environmental concern elsewhere
Forms of Non-Tariff Barriers
-quotas
-restrictive liscenses
-import restrictions and bans
-local laws and national sovereignty
Some examples, taken from the articles:
-Defining the country of origin for textile and apparel imports
-Governments that require purchases of certified sustainably grown wood may not be legal
-U.S. law prohibited the import of shrimp caught in nets that could trap and kill endangered sea turtles. The WTO ruled that the U.S. must allow such imports.
-countries cannot discriminate against ``like'' products based on how they were produced.
-informal non-tariff barriers: These are the most difficult to minimize or eliminate, including unregulated trade (black markets) and corruption.
Technical Barriers to Trade - this is a special class of non-tariff barriers.
-Sanitary and phytosanitary (SPS) regulations
-incongruent standards between nations. i.e. PAL vs. NTSC video standards
Sources:
GATT attack
Anonymous. Business Asia. New York: Dec 5, 1994. Vol. 26, Iss. 25; p. 12 (1 page)
Textile producers ask WTO to help ease export limits
Wall Street Journal (Eastern edition). New York, N.Y.: Jul 19, 1996. p. A9 (3 pages)
Will It Be `Timber!' for Green Logs?; Ecologically certified wood may run afoul of free-trade laws
Marguerite Holloway in New York. Business Week. New York: October 19, 1998. p. 81
International market access issues for forest products
Steven Ruddell, James A Stevens, I J Bourke. Forest Products Journal. Madison: Nov/Dec 1998. Vol. 48, Iss. 11/12; p. 20 (7 pages)
The role of the WTO and the international agencies in SPS standard setting
Swinbank, Alan. Agribusiness. Hoboken: Summer 1999. Vol. 15, Iss. 3; p. 323 (11 pages)
Impact of sanitary and phytosanitary standards on developing countries and the role of the SPS Agreement
Henson, Spencer, Loader, Rupert. Agribusiness. Hoboken: Summer 1999. Vol. 15, Iss. 3; p. 355 (15 pages)
Notes, comments and developments. Some considerations on trade barriers erected for non-economic reasons and WTO obligations
Bernhard Jansen, Maurits Lugard. Journal of International Economic Law. Oxford: Sep 1999. Vol. 2, Iss. 3; p. 530
WTO must eliminate trade barriers on forest products
John Dillon. Pulp & Paper. San Francisco: Oct 1999. Vol. 73, Iss. 10; p. 130 (1 page)
The next trade round
Gary G Yerkey, Lionel Barber, Bruce Barnard. Europe. Washington: Nov 1999. p. 8 (4 pages)
Talks to Lower Trade Barriers
By Geoff Winestock. Wall Street Journal (Eastern edition). New York, N.Y.: Feb 8, 2000. p. A.22
Panel II D: Agreement on technical barriers to trade (TBT) and agreement on the application of sanitary and phytosanitary measures (SPS): Presentation summary and comments
Craig Thorn, Kathleen Ambrose, Kevin Brosch, John Richardson, Martin Wagner. Law and Policy in International Business. Spring 2000. Vol. 31, Iss. 3; p. 869 (2 pages)