Italy is the country with the largest number of low-emission areas in the world, as many as 253. These zones are in fact useful for restricting vehicular traffic and, subject to exceptions, prohibit the movement of certain categories of polluting vehicles within a specific urban area. The findings come from research conducted by GoShorty, which examined the TomTom Congestion Index and the low-emission zones of several countries in the world to determine which of these had the greenest roads. Many of these low-emission areas are located in the northern regions of Italy, in correspondence with larger cities, such as Milan and Venice. The research also offers some other interesting data worldwide related to city traffic. Istanbul is officially the most congested city in the world, with a congestion level of 62%. The residents of the Turkish capital spend about 142 hours in traffic jams, the equivalent of almost six full days.