The Hindu Kush-Himalaya (HKH) is a recognized geographical and environmental concept, defining a vast mountain system often called the "Water Tower of Asia" or the "Third Pole". This region is a continuous arc of mountain ranges, including the Hindu Kush, Karakoram, and the Himalayas, stretching approximately 3,500 kilometers from Afghanistan in the west to Myanmar in the east. The HKH encompasses all or part of eight regional member countries: Afghanistan, Bangladesh, Bhutan, China, India, Myanmar, Nepal, and Pakistan.
The concept's significance stems from its role as the source of ten major Asian river systems, including the Indus, Ganges, and Brahmaputra, which provide water and ecosystem services to nearly two billion people downstream. The HKH holds the largest volume of ice and snow outside the Arctic and Antarctica, with a total glacier area extending up to 87,340 square kilometers. The need for regional cooperation to manage this critical resource led to the formation of the International Centre for Integrated Mountain Development (ICIMOD) in 1983, headquartered in Kathmandu, Nepal. ICIMOD's mission is to promote partnerships among the member countries for sustainable mountain development and to address the challenges of climate change and globalization.
The HKH is currently undergoing rapid and significant change, with the rate of warming estimated to be nearly double the Northern Hemisphere average. Recent assessments by ICIMOD highlight this change: glaciers disappeared 65% faster in the 2010s than in the previous decade, and on current emissions trajectories, up to 80% of the glaciers' current volume could be gone by 2100. Furthermore, the region recorded its lowest snow persistence in recent years, with levels 27% below the long-term average for the winter of 2025–2026, marking the fourth consecutive year of decline. This decline in the cryosphere—the frozen water component—is projected to increase the risk of floods, landslides, and water stress for the downstream population.