Asia’s population is unevenly distributed, mainly because of climatic factors. There is a concentration of population in western Asia as well as great concentrations in the Indian subcontinent and the eastern half of China. There are also appreciable concentrations in the Pacific borderlands and on the islands, but vast areas of Central and North Asia—whose forbidding climates limit agricultural productivity—have remained sparsely populated. Nonetheless, Asia, the most populous of the continents, contains some three-fifths of the world’s people.