Assertion (A): The equatorial region experiences low atmospheric pressure throughout the year despite having high temperatures. Reason (R): Intense solar heating causes warm air to expand, become buoyant, and rise vertically, leading to continuous upward mass transport of air.

💡 Solution & Explanation

The equatorial trough of low pressure, also known as the doldrums, is maintained by thermal convection where continuous high solar radiation heats surface air, causing it to expand, decrease in density, and ascend. This convective vertical movement reduces the mass of air column resting on the surface, establishing low pressure. Surface convergence of trade winds feeds this upward movement, completing the equatorial branch of the Hadley cell.