Homogeneity means the quality or state of being of a similar kind or of having a uniform structure or composition throughout : the quality or state of being homogeneous.
It always depends on some scale
For example let us consider sides of a smooth table.
With our naked eye it may seem homogeneous, but on close observation with a microscope tells us that it is not homogeneous throughout.
We can notice uneven surfaces etc when we look through it
This tells us that homogeneity depends on scale