Article: In 2014 attention was drawn to an appeal to the New Zealand Immigration and Protection Tribunal against the deportation of a Tuvaluan family on the basis that they were "climate change refugees", who would suffer hardship resulting from the environmental degradation of Tuvalu. However the subsequent grant of residence permits to the family was made on grounds unrelated to the refugee claim. The family was successful in their appeal because, under the relevant immigration legislation, there were "exceptional circumstances of a humanitarian nature" that justified the grant of resident permits as the family was integrated into New Zealand society with a sizeable extended family which had effectively relocated to New Zealand. Indeed, in 2013 a claim of a Kiribati man of being a "climate change refugee" under the Convention relating to the Status of Refugees (1951) was determined by the New Zealand High Court to be untenable as there was no persecution or serious harm related to any of the five stipulated Refugee Convention grounds. Permanent migration to Australia and New Zealand, such as for family reunification, requires compliance with the immigration legislation of those countries.

Now answer this question: By what reason was the Tuvaluan family allowed to immigrate?
humanitarian nature