Curitiba, world's greenest cities

Brazil's eighth-largest city, Curitiba is hailed as one of the most sustainable cities in the world. "Curitiba’s city planners have been able to use creative solutions in order to curb emissions, while protecting biodiversity and even alleviating poverty. One of the first issues that city planners in Curitiba had to grapple with was the threat of extreme flooding to the city . . . Rather than build dams that would be expensive and hinder biodiversity, the urban area was instead surrounded by vast fields of grass, which prevent the water from reaching the city and cause destructive flooding. Not only that, but sheep are used to cut the grass instead of machines, which reduces oil consumption and helps to provide farmers with vital resources such as wool for clothing and manure for agriculture. Another way in which the city is sustainable is its bus rapid transit system, used by 1.3 million people, or 75% of the population, per day, which represents a widespread and affordable public transit system that can mitigate carbon emissions from cars. Recycling is also a big part of what makes Curitiba so sustainable, with 70% of the city’s trash being recycled. This has been achieved through a program which allows the city’s residents to exchange recyclables for food, notebooks, and bus tokens, which has been widely successful and helped the impoverished in the city by offering necessities and giving incentives to keep the city’s streets clean." Since 1970, over 1.5 million trees have been planted in Curitiba, along with 28 public parks.