Survivors scrambled for higher ground as torrential monsoon rains swept away homes and triggered landslides across South Asia Tuesday, with millions of people affected and at least 180 dead, officials said. The monsoon is crucial for irrigation and groundwater supplies in the impoverished region, home to a fifth of the world's population, and brings relief after the unforgiving summer.

But the downpours, which stretch from June to September, can turn deadly, and have wreaked havoc again this year across India, Nepal, Bangladesh and Pakistan-administered Kashmir, with people, dwellings and boats in remote low-lying areas washed away. "Entire communities have been cut off by rising waters, increasing the risk of people going hungry and getting sick," Xavier Castellanos, of the International Federation of Red Cross, said of the growing crisis.

Almost a third of Bangladesh, a delta country crisscrossed by hundreds of rivers, was underwater, Arifuzzaman Bhuyan of the state-run Flood Forecasting and Warning Centre told AFP. In Nepal, at least 78 people died and 16,000 families were displaced, although flood waters have started receding. Nearly 50 people have been killed in India, with two eastern states, Assam and Bihar, which borders Nepal, bearing the brunt of the deluge. Authorities in Assam declared a red alert Monday as the flood situation turned critical, with villages cut off by surging waters and a major highway submerged.