What do you understand by the phenomenon of temperature inversion in meteorology? How does it affect the weather and the habitants of the place? (UPSC 2013)

Temperature inversion is a reversal of the normal lapse rate, when air near the ground becomes cooler than the air above it. Instead of rising and mixing, the cold, dense air is trapped below a warm layer, like a lid.

• Weather: it checks convection, so clouds, winds and rainfall are reduced; fog, frost and smog become common.
• Habitants: pollutants remain trapped, worsening air quality and causing breathing and heart problems. Visibility falls, disrupting transport, while crops may suffer frost damage.

Thus, inversion makes the atmosphere stable but often unhealthy, especially in winter and valleys.