Section 94(1)(a) in Sikkim Urban and Regional Planning and Development Act, 1998
(a)No person shall within the area included in the regional planning area or the development area, as the case may be, erect or proceed with any building work, remove, pull down, alter make additions to or make any substantial repair to any building, part of building, a compound wall or any drainage work or remove any earth, stone or material, or sub-divide any land or charge the use of any land or building unless such person has applied for and obtained necessary permission from the Chief Town Planner or such other authority as may be desired by Government in the case of regional planning area and the Authority in the case of development area under its jurisdiction;