Is it forbidden to give bank interest to the poor and needy instead of taking it home, and is this interest considered part of zakat al-mal, and is that permissible, and what should one do if the money decreases due to paying zakat on it over the years if it is placed in the bank without interest?

It is not permissible to deposit money in usurious banks, even if the depositor does not take interest, because the one who enables usury is like the one who consumes it in sin, due to the Almighty's saying: "And do not cooperate in sin and aggression." And the Prophet, peace and blessings be upon him, cursed the consumer of usury, its enabler, its scribe, and its two witnesses.

The obligatory zakat on usurious deposits is the zakat on the principal amount deposited, and the zakat is not from the illicit interest, due to the Almighty's saying: "And do not aim for the bad to spend from it."

Usurious gains are illicit money that cannot be utilized. They should be spent on charitable causes and public interests with the intention of getting rid of them, not as charity. The depositor is entitled only to their principal capital.

Allah Almighty has permitted lawful means of earning that suffice one from the forbidden.