The "walking on clouds" effect on Volcán Chimborazo, and other high mountains, occurs due to several factors related to altitude, climate and geography. 

 Is it flat ground?  

 The terrain at Volcán Chimborazo is not flat; in fact, it is quite rugged and steep, as is typical of volcanic mountains. Chimborazo is a stratovolcano, which means it is conical in shape, with steep slopes that vary in steepness as you climb. 

 Chimborazo is over 20,000 feet high. At high altitudes, you are often above the clouds that form in the lower layers of the atmosphere. So when you look down, it feels like you are "walking" on them.

Chimborazo is the furthest point from the center of the Earth, further than Everest. This is due to the elliptical shape of the Earth, which is widest at the equatorial region.