Asia is the largest of the world’s continents, covering an area of 44,579,000 square kilometers (17,212,000 sq mi), approximately 30 percent of the Earth’s land area. Asia is bounded on the east by the Pacific Ocean, on the south by the Indian Ocean, and on the north by the Arctic Ocean. It is also the world’s most populous continent, with roughly 60 percent of the total population; the continent has a population of 4.5 billion people as of 2021. Asian countries rank as some of the top producers of many agricultural, forest, fishing, mining, and industrial products. Rapid growth, however, has meant further advancements into natural areas, and particularly in the subtropical and tropical areas, which has led to human encounters with new diseases. Infrastructure in developing countries in Asia remains far from adequate, with more than 400 million Asians still lacking electricity; roughly 300 million having no access to safe drinking water and 1.5 billion lacking basic sanitation.