GIs are denominations that identify a good as originating in a region or locality, where the reputation and quality of good is essentially attributable to its geographical origin (for example: Darjeeling tea of India)
TRIPS prohibits the use of GIs in such a way as to cause deception and provides for injunctive relief, refusal of trademark registration, etc.
Exception: Countries are not required to bring a geographical indication under protection, where it has become a generic term for describing the product in question.