Trekking in the low season would be the best reason to avoid a high number of trekkers for your own peacefulness environment. Upper Mustang the Rainshadow areas in Nepal. Visiting the Upper Mustang area one of the scenic trekking trails during the monsoon season in Nepal.
Upper Mustang was once the independent Himalayan Kingdom that was later commandeered into Nepal’s territory, Upper Mustang is one of the restricted trekking destinations in Nepal that requires a special permit which you could only obtain from the registered trekking companies. Individual trekkers are not allowed to trek in restricted areas.
Mostly the Buddhists who once followed the Bon religion are inhabits Upper Mustang. Mustang lies in the rain-shadow area of the Annapurna range. This means that the region experiences less rainfall making it perfect for the trekkers to trek even during monsoon season.