Why the earth bulges at the equator?

The Earth bulges at the equator due to its rotation. As the planet spins, centrifugal force pushes outward at the equator, causing the equatorial region to extend slightly. This shape, known as an oblate spheroid, results in the equatorial diameter being about 43 kilometers (27 miles) larger than the polar diameter. Additionally, the distribution of mass and the gravitational pull contribute to this equatorial bulge.