(i)in the' [Kolkata] [Substituted by section 5 of the West Bengal Capital City (Change of Name) Act, 2001 (West Bengal Act No. 18 of 2001) (w.r.e.f. 1.1.2001) for the word Calcutta.] district, the person appointed under section 7, [sub-section (2),] [Inserted by section 3(3) of the Bengal Excise (Amendment) Act, 1965 (West Bengal Act 39 of 1965).] clause (b), to exercise all the powers and to perform all the duties of the Collector in that district, and