(b)"fissile material" means uranium-233, uranium-235, plutonium or any material containing these substances or any other material that may be declared as such by notification by the Central Government;(bb)[ "Government company" means a company in which-(i)not less than fifty-one per cent. of the paid-up share capital is held by the Central Government; or(ii)the whole of the paid-up share capital is held by one or more of the companies specified in sub-clause (i) and which, by its articles of association, empowers the Central Government to constitute and reconstitute its Board of Directors;]