Explanation:
Concept overview / definition
Surface air pressure depends on the weight of the air column above a place. When air near the surface is strongly heated, it expands, becomes lighter and rises upward, leaving less mass in that column. Conversely, when air cools and sinks, it adds extra mass to the column and increases the weight pressing on the ground. These vertical motions linked with heating and cooling create low-pressure and high-pressure areas that drive winds at the surface.
Why the correct option is correct
Statement 1 is correct because intense heating over land makes the air above expand and rise, so the pressure at the surface falls and a low-pressure region forms. Statement 2 is correct because cooling makes air denser; as this dense air descends, it accumulates near the surface, increasing the weight of the air column and leading to high pressure. Together, these processes explain why warm regions often develop low pressure, while cooler, subsiding regions tend to show high pressure.
Why the other options are incorrect
Statement 3 is incorrect because at the surface winds blow from high-pressure areas toward low-pressure areas, not the reverse. The pressure gradient force pushes air down the pressure slope from where the air column is heavier toward where it is lighter. Therefore any option that claims a general flow from low to high pressure at the surface contradicts the basic definition of surface winds in climatology.
UPSC exam tip / common confusion
Many students memorise that warm air means low pressure and cold air means high pressure, but forget the link with vertical motion and wind direction. In exam questions, first think about what heating or cooling does to density, then to rising or sinking, and only then to pressure. Finally, remember that surface winds move from high to low pressure, while patterns in the upper troposphere can look different and sometimes create confusion in diagrams.
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