Assertion (A): Deserts located on the western margins of continents in subtropical latitudes experience hyper-arid conditions. Reason (R): Cold ocean currents flowing equatorward along these western coasts stabilize the lower troposphere, suppressing convective cloud formation and precipitation.

💡 Solution & Explanation

Both assertion and reason are true, and the reason correctly explains the phenomenon. Equatorward-flowing cold ocean currents cool the air immediately above them, creating a thermal inversion that inhibits warm air from rising and forming rain-producing clouds. This atmospheric stability maintains hyper-arid conditions along western continental margins such as the Namib and Atacama deserts. Subtropical high-pressure descending air also contributes significantly to this aridity.