The free fall acceleration g increases as one proceeds, at sea level, from the equator toward either pole. The reason is

The acceleration due to gravity (g) is not uniform across the Earth's surface. Earth is not a perfect sphere but an oblate spheroid or ellipsoid [3]. Due to the centrifugal force generated by Earth's rotation, the planet bulges at the equator and flattens at the poles [2]. This results in an equatorial radius that is approximately 21 km greater than the polar radius [3]. According to Newton's law of universal gravitation, the force of gravity is inversely proportional to the square of the distance from the center of mass. Consequently, an observer at the poles is closer to the Earth's center than one at the equator, leading to a higher value of g at the poles [2]. Additionally, the centrifugal force is maximum at the equator and zero at the poles, further reducing the effective gravity at the equatorial region [4].

Sources

1. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 7: Tectonics > Forces Behind The Drifting Of Continents (According to Wegener) > p. 95
2. [3] https://en.wikipedia.org/wiki/Equatorial_bulge
3. [1] FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 2: The Origin and Evolution of the Earth > Indirect Sources > p. 19
4. [4] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 23: Pressure Systems and Wind System > Causes of The Coriolis Effect > p. 309