In a real atmosphere, density decreases with elevation above mean sea level.

The average density of the balloon decreases less than that of the surrounding air.

This is true even if the density of the fluid decreases upward.

If you venture above sea level, air pressure and its corresponding density will decrease.

The record was set due to the high altitude where the lesser density of the atmosphere decreased drag.

The density of the river network increases, then gradually decreases later with higher altitudes.

In this case of a fixed mass, the density decreases as the volume increases.

The density of the Earth's atmosphere decreases nearly exponentially with altitude.

They are spread out symmetrically, but the density of stars decreases with distance from the core.