Sec. 3.1. (a) Except as otherwise provided in subsection (b), income is not exempt from the adjusted gross income tax under section 2.8(1) of this chapter if the income is derived by the exempt organization from an unrelated trade or business, as defined in Section 513 of the Internal Revenue Code.
(b) This section does not apply to:
(1) the United States government;
(2) an agency or instrumentality of the United States government;
(3) this state;
(4) a state agency, as defined in IC 34-6-2.1-194;
(5) a political subdivision, as defined in IC 34-6-2.1-155; or
(6) a county solid waste management district or a joint solid waste management district established under IC 13-21 or IC 13-9.5-2 (before its repeal).