Kathmandu, Aug. 29 -- On the morning of 20 May this year, we dragged ourselves up to Gokyo Ri, the famous viewpoint in the Khumbu. Four of the world's six highest mountains sliced the crystal-clear air in a spellbinding scene that had inspired us to visit Nepal.

The only problem was that we were alone. In normal times, a May morning with perfect weather would have meant throngs of trekkers on the trails. The solitude was lucky for us, but a telltale sign of the grave risk that Nepal's tourism-dependent regions now face.

My girlfriend Mallika, our guide Kedar, and I were among the last trekkers in the Khumbu in Spring 2021. For 16 days, we had the trails, hotels, and even whole villages to ourselves. We spoke with many locals whose livel...