Is it permissible for an emigrant to appoint someone in his home country to distribute the zakat on his wealth that has been due for a year, or must he wait until he returns to distribute it himself?

Zakat must be paid immediately upon becoming due and when one is able to do so. It is not permissible to delay it except for a valid excuse. A Muslim who is far from their wealth should appoint someone to pay Zakat on their behalf in the country where the wealth is located, because delaying it deprives its rightful recipients, and death may overtake one before returning.