Sneakers (US) or trainers (UK), also known by a wide variety of other names, are shoes primarily designed for sports or other forms of physical exercise but which are also widely used for everyday casual wear.
Since their popularization by companies such as Converse, Nike and Spalding in the mid 20th century, they have become attire,[clarification needed] with variety growing in many global markets exponentially.[clarification needed] Like other parts of the global clothing industry, shoe manufacturing is heavily concentrated in Asia with nine in ten shoes produced there.
Contemporary sneakers are largely made from synthetic materials, and the materials and manufacturing process produce, on average, about 14 kg (31 lb) of CO2 emissions. Some companies are trying to substitute more sustainable materials in their manufacture. About 90% of shoes end up in landfills at end of life.