(Speed of light in vacuum/air = 299 792 458 m/s ≈ 3 × 10 ⁸ m/s)
The speed of light varies from one medium to the other.
It depends on the nature of the medium.
In space, which is nothing but vacuum, the speed of light is equal to 3 × 10^8 m/s.
However, on land it changes from one medium to the other.