Explanation
Statement I is correct. Dust particles are more concentrated in
subtropical and temperate regions due to a combination of factors. These regions are home to major
arid and semi-arid climates, with large deserts such as the
Sahara, Arabian Desert, and Thar Desert — all located in subtropical zones — acting as prime sources of atmospheric dust. The
lack of vegetation cover and
strong dry winds promote the suspension of dust particles in the atmosphere. In contrast,
equatorial regions are humid and densely vegetated, where frequent
rainfall and plant cover suppress dust.
Polar regions are cold and ice-covered, which similarly limits dust production and suspension.
Statement II is incorrect. Subtropical regions are not characterized by
less dry winds — quite the opposite. The
subtropical high-pressure belts are associated with
descending air masses, which create
dry, stable, and arid conditions. These descending air currents result in
low humidity, clear skies, and strong dry winds — precisely the conditions that make subtropical regions
dustier, not less so. It is these very dry winds that explain why dust concentration is higher in subtropical and temperate areas. Statement II therefore not only fails to explain Statement I — it
directly contradicts the actual atmospheric dynamics of subtropical regions.
Therefore,
Statement I is correct but Statement II is incorrect.