2. In madaris all type of people (earnings from halal and haram) give zakah and it is used for students in madaris without inquiry, is it lawful?
بسم الله الرحمن الرحيم
(Fatwa: 598/494/B=05/1440)
The later Fuqha have allowed taking fee on teaching the Holy Quran for Shariah needs, so it is lawful to receive fee for teaching the Holy Quran.
ويفتى الیوم بصحتها لتعليم القرآن والفقه والإمامة والأذان وفي رد المحتار: قال في الهداية: وبعض مشايخنا رحمهم الله استحسنوا الاستئجار على تعليم القرآن اليوم لظهور التواني في الأمور الدينية ففى الامتناع تضييع حفظ القرآن وعليه الفتوى (الدر المختار مع رد المحتار، كتاب الإجارة، باب الإجارة الفاسده، 9/ 76، ط: زكريا)
(2) If you know for sure that the zakah of so and so person is from haram wealth then it is not lawful to take zakah from him and if you are not sure then there is no need to investigate it thoroughly.
Allah knows Best!
Darul Ifta,
Darul Uloom Deoband