By the 1980s a deadly cocktail of factory fumes and car exhausts had turned Mexico City into the world's most polluted city. Hundreds of thousands of people were falling ill each month, many of them children. The Mexican authorities came up with an ambitious plan to curb the use of each of the city's two million cars for one day a week. The scheme was an immediate success and has been copied in other major cities around the world. Ramon Ojeda Mestre, the environmentalist behind the Mexican initiative spoke to Mike Lanchin about overcoming fierce opposition to the plan.
Photo: Cars driving through Mexico City. Credit: Alamy