Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.
As a rule, one has to pay Zakah in the place of his residence, i.e. where it becomes a duty on him.
There is agreement among Fuqaha that it is permissible to transfer Zakah - wholly or partially - if the needs of the city residents have been satisfied or if there are no eligible people in that area to receive it or there is much money of Zakah.
They also agree that if one transfers Zakah, although the needs of the city residents have not been satisfied, that will suffice, i.e. it will be sufficient for the obligation.
al-Qari , in his explanation of al-Mishkah from al-Tibi , said: 'Fuqaha agree that if one transfers his Zakah and pays it, that will suffice the obligation. Only Umar Ibn 'Abdul 'Aziz returned the Zakah transferred from Khurasaan to Syria, i.e. to its place of collection' . al-Qari added: ' Umar 's action demonstrates the perfect justice and constitutes an indication to prevent greed, not a violation to the general agreement' .
Fuqaha differ concerning if one who transfers Zakah, without a genuine reason, sinful or not.
al-Shafiyah and al-Hanabila consider him sinful, while al-Ahnaf do not think so. Ahnaf state that transferring Zakah is disliked unless it is for needy relatives and serves the ties of blood or when the needs of a group of Muslims are more pressing than those of the locals, when it is tied to the general interests of the Muslims, when it is sought from a country at war against the Muslims to the land of Islam, when it is intended for a scholar/student to help him in his mission, when it is sent to a righteous one, when it is paid before the completion of the Hawl. In those cases, transferring Zakah is not disliked'. And this is the dominant opinion. Ibn Taymiyah holds the same opinion: 'There is no Sharia evidence for those who state that transferring Zakah is not allowed beyond the distance of shortening the prayer. Then, it is permissible to transfer Zakah as long as there Sharia interest' . This opinion constitutes a legal rebuttal to the opinion of Malikiyah who believe that it is not permissible to transfer Zakah from its place of origin to that of the place beyond which shortening prayer is applicable. It must be spent in the place which generated it or near it, but not beyond the point of Qasr (shortening prayer). They added: 'if there is no anyone who is eligible to receive Zakah in its place of origin or near it, then it should be transferred to a place (within the distance of shortening prayer) where there is one who is eligible to receive it.
In other words, it is not permissible to transfer it except as shown above unless there is one who is in a dire need, then it is recommendable to transfer it. Here are two cases:
1) To transfer Zakah to another person who is in equal need with those who are in the place of origin. This is not permitted although it is sufficient for obligation.
2) To transfer Zakah to another person who is in less need if compared with those who are in the place of origin. Here are two sub-cases: (a) It does suffice the obligation according to some scholar, and (b) according to Ibn Rushd and others, it is sufficient since it was paid to those who are entitled to receive it.
For more details, please check "Fiqh al-Zakah" of al-Sheikh Yusuf al-Qaradawi (may Allah grant him long life).
For the other details please read the Fatawa:
87401 and81332.
Allah knows best.