Why acceleration due to gravity is the example of uniform acceleration?

If the rate of increase of velocity of a moving body in a particular direction is maintained constant all the time, then the acceleration is said to be uniform.

An example of uniform acceleration is the gravitational acceleration. Due to gravity, the acceleration of a freely falling body is 9.8 m/s2, that is, its velocity increases by 9.8 m/s for each successive seconds. So, gravitational acceleration is an example of uniform acceleration.