The influx of foreigners has added to pressures on the Himalayan environment, but it hasn't spoiled the friendliness of Nepalis, surely among the most welcoming people on earth.
The Himalayan environment has thrived at the influx of foreigners. 
mnli hypothesis: The Himalayan environment has thrived at the influx of foreigners.  premise: The influx of foreigners has added to pressures on the Himalayan environment, but it hasn't spoiled the friendliness of Nepalis, surely among the most welcoming people on earth.