Question

The air of hills of cooler than that of plains.

Answer 1

This is because of high altitude

Answer 2

At sea level, the atmospheric pressure is more and in a HILL STATION the Atmospheric pressure is comparatively LESS. As Pressure decreases ,the Temperature also Decreases. ... The water vapour present at HILL STATIONS is LESS so there is less absorption of HEAT from the SUN which prevents the rise of temperature.