Assertion(A): Tropical cyclones do not develop very close to the Equator. Reason (R) : A weak coriolis effect retards the development of circular air motion.

Assertion (A) is true because tropical cyclones rarely form within 0° to 5° latitude of the Equator [3]. Reason (R) correctly explains this phenomenon: the Coriolis force is zero at the Equator and increases with latitude [2]. A strong Coriolis force is a necessary condition for cyclogenesis as it deflects inward-moving winds, creating the spiraling motion required for a cyclonic vortex [5]. Near the Equator, the weak or absent Coriolis effect prevents this rotation; instead, air flows directly into low-pressure areas, filling them rather than allowing them to intensify into organized storms [4]. Consequently, the lack of sufficient rotational force retards the development of circular air motion, making the Reason a valid explanation for the Assertion [3].

Sources

1. [3] INDIA PHYSICAL ENVIRONMENT, Geography Class XI (NCERT 2025 ed.) > Chapter 6: Natural Hazards and Disasters > Tropical Cyclone > p. 60
2. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 26: Tropical Cyclones > Coriolis Force > p. 356
3. [2] FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 9: Atmospheric Circulation and Weather Systems > Coriolis Force > p. 79
4. [4] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 23: Pressure Systems and Wind System > Why Tropical Cyclones Do Not Form At The Equator? > p. 309
5. [5] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 23: Pressure Systems and Wind System > Why Tropical Cyclones Do Not Form At The Equator? > p. 310