Clouds may also develop as a consequence of human activity. Examples are aircraft condensation trails (contrails), or clouds resulting from industrial processes, such as cumuliform clouds generated by rising thermals above power station cooling towers. Clouds that are clearly observed to have originated specifically as a consequence of human activity will be given the name of the appropriate genus, followed by the special cloud name “homogenitus”. For example, Cumulus cloud formed above industrial plants will be known as Cumulus (and, if appropriate, the species, variety and any supplementary features) followed by the special cloud name homogenitus; for example, Cumulus mediocris homogenitus.