Section 2(90) in Assam Notified Urban Areas (Other than Guwahati) Building Rules, 2014
(90)"permanent open air space" means an air space permanently open ,-(a)if it is a street;(b)if it is free from encroachment, is protected by any law or contract ensuring that the ground below it is either a street or is permanently and irrevocably appropriated as an open space;
