Air is everywhere. Water is also available everywhere as there is no living possible without air and water. So, water and air are available mostly everywhere on the earth and hence they are ubiquitous resources. Iron and coal are resources that can not be found everywhere and hence they are called localised resources because their availability is dependent upon the specific location. In addition, air and water are available regardless of location and ownership. Resources that are available at specific locations are called localised and resources that are available everywhere are called ubiquitous resources. So, air and water are ubiquitous resources and coal and iron are localised resources.