South Asia: Mountains, Plains, Plateaus, and Monsoons

South Asia includes India, Pakistan, Bangladesh, Nepal, Bhutan, Sri Lanka, and Maldives. Together, these countries contain an enormous range of physical environments. High mountains form much of the region's northern edge, while broad plains stretch across northern India, Pakistan, and Bangladesh. Farther south, much of peninsular India consists of higher land surrounded by coastal plains and the Indian Ocean.

The Himalayas form a massive mountain system across the northern part of South Asia. Mount Everest, the highest point above sea level on Earth, lies in the Himalayas along the border between Nepal and China. Other high mountain systems include the Karakoram and the Hindu Kush, which extend through northwestern parts of the broader region.

These mountains affect more than elevation. They influence the movement of air and moisture, help feed major rivers with snow and ice, and make transportation difficult in many places. Elevation also affects climate, so the highest parts of the region remain much colder than the lowlands to the south.

South of the mountains lies a broad area of relatively low, flat land built partly by sediment carried by rivers. This area includes the Indus River system in Pakistan and the Ganges and Brahmaputra river systems farther east. Rivers flowing from the mountains carry water and sediment onto the plains before eventually reaching the Arabian Sea or Bay of Bengal.

Over long periods of time, these rivers have created large areas of fertile soil. Flat land, available water, and productive farmland have made the plains important for agriculture, transportation, and settlement. Flooding can renew soil with sediment, but severe floods can also damage homes, farms, roads, and other infrastructure.

Much of southern India is part of the Deccan Plateau, an elevated region that covers a large portion of the peninsula. The Western Ghats and Eastern Ghats run along parts of the plateau's edges. Narrower coastal plains lie between these highlands and the sea.

Peninsular India extends southward into the Indian Ocean, with the Arabian Sea to the west and the Bay of Bengal to the east. Sri Lanka lies just southeast of India, while Maldives consists of many small islands farther southwest in the Indian Ocean. The region's long coastlines have helped connect South Asia with maritime trade routes for thousands of years.

South Asia's climate varies greatly. Elevation keeps the highest mountain areas very cold, while much of the southern region experiences tropical conditions. Northwestern areas are much drier, and rainfall varies greatly across the subcontinent.

One of the region's most important climate patterns is the monsoon. A monsoon is a seasonal change in wind direction. During much of the summer, moist air moves inland from the ocean and brings heavy rainfall to many areas. During the winter, winds generally carry much less moisture from the land toward the ocean.

Monsoon rainfall is important for farming and water supplies, but the amount and timing of rain can vary. Too little rain can contribute to drought, while very heavy rain can cause flooding. South Asia's physical geography therefore creates both resources and challenges for the people who live there.