Section 2(c) in The Bombay Electricity Duty Rules, 1962
(c)"billing month" means a month in respect of which a bill of charges is prepared by a licensee under his tariffs for the supply of energy to his consumers. Where more than half the number of days of such month fall in any calendar month, such month shall be named after that calendar month, and where equal number of days of such month fall in two calendar months, such months shall be named after the first of the Two calendar months;
