Section 126A(2) in The Representation of the People Act, 1951
(2)For the purposes of sub-section (1), the Election Commission shall, by a general order, notify the date and time having due regard to the following, namely:--(a)in case of a general election, the period may commence from the beginning of the hours fixed for poll on the first day of poll and continue till half an hour after closing of the poll in all the States and Union territories;(b)in case of a bye-election or a number of bye elections held together, the period may commence from the beginning of the hours fixed for poll on and from the first day of poll and continue till half an hour after closing of the poll:Provided that in case of a number of bye-elections held together on different days, the period may commence from the beginning of the hours fixed for poll on the first day of poll and continue till half an hour after closing of the last poll.