Section 346(3) in Kolkata Municipal Corporation Act, 1980
(3)The Mayor-in-Council shall, from time to time, specify the minimum widths of different categories of public streets without regard to the existing widths of such streets as may be included in such categories :Provided that the minimum width of any public street falling under category I or category II or category III or category IV shall not be less than ten metres including any public street falling under category VI and that of a public street falling under category V, not less than six metres:Provided further that such minimum widths may be revised by the Mayor-in-Council at an interval of not less than five years.