بسم الله الرحمن الرحيم
Paying income tax with interest money received from government banks is equal to returning the amount towards its owner; hence it is allowable to pay income tax with interest received from government banks. It is not the case with the private bank interest; hence it is not lawful to pay income tax with interest money received from the private bank.
قال فى الشامي: لأن سبيل الكسب الخبيث التصدق إذا تعذر الرد على صاحبه . (شامى: 9/553 ط: زكريا ديوبند)
Allah knows Best!
Darul Uloom Deoband