Is zakat obligatory on money saved for marriage? If so, what is its amount? And does distributing the interest to the poor suffice for zakat?

It is not permissible to deposit money in a usurious bank, and it is obligatory to withdraw it and place it in an Islamic bank if one is available, or to keep it in another place. If you are compelled to place it in a usurious bank, then put it in a current account to avoid interest.

If usurious interest accrues on the money, it is forbidden to benefit from it, and it must be spent on charitable causes, such as giving it to the poor or for the benefit of Muslims. Distributing this interest does not exempt one from the obligatory zakat due on this saved money if it reaches the nisab (minimum threshold) and a full year has passed.