Hazardous substance specification framework allows the Central Government to identify relevant income sources and substance quantities by order. The Central Government may specify, by general or special order issued from time to time, the income from sources referred to in the Explanation to clause (x) of sub-section (1) of section 2 and the substance, or quantity of substance, referred to in clause (zb) of that sub-section. The rule operates as an enabling provision for periodic specification through executive orders.