Generalized System of Preferences ( GSP)
The Generalized System of Preferences, or GSP, is a preferential tariff system which provides for a formal system of exemption from the more general rules of the World Trade Organization (WTO), (formerly, the General Agreement on Tariffs and Trade or GATT). Specifically, it's a system of exemption from the most favored nation principle (MFN) that obliges WTO member countries to treat the imports of all other WTO member countries no worse than they treat the imports of their "most favored" trading partner. In essence, MFN requires WTO member countries to treat imports coming from all other WTO member countries equally, that is, by imposing equal tariffs on them, etc.
GSP exempts WTO member countries from MFN for the purpose of lowering tariffs for the least developed countries, without also lowering tariffs for rich countries
Duty-Free, Quota-Free ( DFQF) Market Access
Duty-free and quota-free market access for LDCs
In the 2005 Hong Kong Ministerial Conference, members adopted a Decision on Measures in Favour of Least-Developed Countries where developed countries, and developing-country members declaring themselves in a position to do so, agreed to implement duty-free and quota-free (DFQF) market access for products originating from LDCs.
WTO AGREEMENT ON TRADE FACILITATION_931
Special and Differential Treatment under Trade Facilitation for LDCs
Duty-Free Quota-Free Schemes for LDCs in major markets 2014
Duty-Free & Quota-Free (DFQF) Market Access in India, China & South Korea