Ans.

Equatorial Low-Pressure Belt: – This belt is situated between 5° North and 5° South latitudes on both sides of the equator.  Due to the vertical fall of the sun’s rays, the temperature here remains high throughout the year, due to which the air here expands after getting warm and keeps rising after becoming lighter.  Due to this low air mass is found here.  Here there is also the sum of the abundance of vapor in reducing the air mass.  Here the wind never moves parallel to the surface, but due to the formation of convectional currents in the air, the speed of the winds remains vertical.  Therefore, it is a calm belt which is called calm Mandal or doldrums.

Polar High-Pressure Belts: – The sun’s rays fall very obliquely near both poles, due to which the temperature there remains very low.  Therefore, even though the air cover is very thin, due to the low temperature, the high air mass is found here.