Madrid is the European city with the highest number of trees and green surface per inhabitant and it has the second highest number of aligned trees in the world, with 248,000 units, only exceeded by Tokyo. Madrid's citizens have access to a green area within a 15-minute walk. Since 1997, green areas have increased by 16%. At present, 8.2% of Madrid's grounds are green areas, meaning that there are  of green area per inhabitant, far exceeding the  per inhabitant recommended by the World Health Organization.