South Asia faces a twin crisis due to an alarming reduction in snow cover across the Hindu Kush Himalayan (HKH) region, posing a serious threat to water security for nearly two billion people in India and neighbouring countries.

According to the 2025 Hindu Kush Himalayan Snow Update by the International Centre for Integrated Mountain Development (ICIMOD), snow presence on the ground between November and March was 23.6 percent below normal -- marking the lowest level recorded in the past 23 years.

On average, snowmelt contributes about 23 percent to the annual water flow in major river basins.

The report warns that this continued snow deficit could severely impact water supply for agriculture, drinking, and hydropower, especially during the dry season when snowmelt plays a vital role in sustaining river flows.

While the Indian Meteorological Department suggests that reduced snow cover may favour an above-normal southwest monsoon this year, ICIMOD, an intergovernmental body, highlights the risk it poses to long-term water availability in the region.

This marks the third consecutive year of below-normal seasonal snow across the HKH region, the report said, quoting data from PTI. Snow that typically accumulates during the winter is either falling in reduced amounts or melting earlier than expected.

All 12 major river basins in the HKH region -- including those in India, China, Pakistan, Afghanistan, and Southeast Asia -- recorded below-normal snow levels. The situation is particularly severe in the Mekong and Salween basins, with snow persistence 51.9 percent and 48.3 percent below normal, respectively.

In India, the Ganges and Brahmaputra river systems have recorded major snow deficits. The Ganges basin saw its lowest snow persistence in more than 20 years -- 24.1 percent below normal -- raising concerns over reduced water availability in early summer, when demand for irrigation and drinking is high.

In the Brahmaputra basin, snow persistence was down 27.9 percent, potentially impacting agriculture and hydropower generation. The Indus basin, which supports millions in both India and Pakistan, also reported continued snow cover decline. Though the 2025 drop was slightly less severe than in 2024, it still remained 16 percent below normal.

ICIMOD Director General Pema Gyamtsho said carbon emissions have already locked the region into an irreversible trend of recurring snow anomalies.

Sher Muhammad, remote sensing specialist at ICIMOD and lead expert on the report, said, "We are observing such deficit situations occurring in continuous succession. This is an alarming trend. While our findings give a broad picture across the region, each must act based on the specific conditions of their river basins, particularly where seasonal snowmelt is the major water source."