Local context review is required on international research if the country where the study will be conducted does not have human subjects regulations that require local (in-country) review of the research. Local context review is sometimes required for subcultures within the US as well.
Countries do not require local context reviews. This is something that is required by the Clemson University Office of Research Compliance (ORC) / Institutional Review Board (IRB) in order to ensure that we are appropriately assessing risk to participants in cultures we are not familiar with.
However, unrelated to the fact that local context reviews are a requirement of the CU ORC / IRB, there are significant differences in the regulation of human subjects research across different countries. Some countries have human subjects regulations and require governmental approval for all research being conducted in the country, and some countries do not have any regulations, or have regulations that only address biomedical human subjects research. If a country requires local review, the CU ORC / IRB will accept that review in lieu of an independent local context review.
If you are interested in learning more about the regulations in a particular country, the Office for Human Research Protections (OHRP) publishes a list of international regulations related to human subjects research on an annual basis, http://www.hhs.gov/ohrp/international/intlcompilation/intlcompilation.html