"Not many people realise that the UN has one definition of 'refugee' for Palestinian refugees, and a completely different definition for all of the world's other refugees, and one agency that deals with Palestinian refugees (UNRWA) and a completely different agency to look after all of the world's other refugees (UNHCR).
UNRWA was established in December 1949 by UN General Assembly resolution 302. It defines 'Palestine refugees' not only as 'persons whose normal place of residence was Palestine during the period 1 June 1946 to 15 May 1948, and who lost both home and means of livelihood as a result of the 1948 conflict,' but also their descendants - ad infinitum.
Fewer than 1% of the people currently served by UNRWA fled from their homes during the 1948 or 1967 wars against Israel. The rest are descendants of refugees, many of whom are natives of other countries or enjoy full citizenship rights or permanent residency in other countries. Some have become refugees from other conflicts, such as the civil war in Syria.
The notion of refugee status being inherited and passed down in perpetuity to remote descendants who have never fled from their homes is without parallel in international law. It is not applied to, nor is it claimed by, any other refugee group...
There appears to be no good reason why there is one UN agency and one set of rules for Palestinian refugees and another agency and another set of rules for all of the world's other refugees. UNRWA explains this anomaly thus: 'As UNRWA was set up in 1949, Palestine refugees were specifically and intentionally excluded from the international refugee law regime established in 1951.'
However, this explanation only provides the historical reason for the existence of the two agencies, not a justification, and does not give a reason why the two agencies should not be merged, and why the criteria for determining who is a refugee should not be standardised, so that the same rules apply to everybody."