[pashsdk27]

The biggest reason why most people prefer to live near the rivers in this region is water. A lot of the villages up in the mountains do not have running water and you have to hike a few kilometers down the valley to get water from hand-pumps and small streams. That was the case when I last visited my grandparent's village in Uttarakhand. Even my hometown which is one of the largest towns in the region has water problems. It gets worse the higher you go in the Himalayas.

Landslides are also a major factor as the mountains are extremely fragile. I've witnessed several such small landslides during my trips that often block the small mountain roads. They are very common.

There is pretty much no usable agricultural land and most villages rely on money from people working outside the region or small scale cattle domestication. Upper Himalayas is a rough terrain and so not many people live there. Living closer to the rivers is much better. Even better is living closer to the major roads that often are closer to the rivers.

Things are slowly and steadily improving these days. The regulations are also being more strictly enforced. Though I'm quite concerned that many similar disasters will happen in the future due to climate change. :/