Section 64(2) in The Bihar Panchayat Raj Act, 2006
(2)For the convenience of election the District Magistrate shall in accordance with such Rules as may be prescribed in this behalf by the State Government divide the area of the Zila Parishad under the direction, control and supervision of the State Election Commission into territorial constituencies in such manner that the population of each territorial constituency, so far as practicable, be the same throughout the Zila Parishad area.
