20. (1) The Chairman or any other person authorised by him in writing may enter upon and survey any land, undertake investigations, erect pillars for the determination of areas and intended lines of works, make borings and excavation for the discovery of minerals, and do all other acts which may be necessary in order to carry out all or any of the purposes of this Ordinance: Provided that when the affected land does not vest in the Corporation, powers conferred by this sub-section shall be exercised in such manner as to cause the least interference with, and the least damage to, the rights of the owner thereof. (2) When any person enters into or upon any land in pursuance of sub-section (1), he shall, at the time of entering, pay or tender payment for all necessary damage to be done as aforesaid and in case of dispute as to the sufficiency of the amount so paid or tendered, he shall at once refer the dispute to the Corporation whose decision shall be final. (3) It shall be lawful for any person authorised under sub-section (1) to make an entry upon any land, to open or cause to be opened a door, gate or other barrier,-(a) if he considers the opening thereof necessary for the purpose of such entry;(b) if the occupier or owner, as the case may be, is absent, or being present refuses to open door, gate or barrier: Provided that the compensation shall be paid for the damage caused in such manner as the Corporation may prescribe, and in case of dispute as to the sufficiency of the amount, the matter shall be referred to the Corporation whose decision shall be final.