It is called cellulite, JThomp42 is correct on that, however, it is preventable and reversible.
The main reason more women are experiencing this is the same reason more men are walking around with more fat too.
When you eat more calories than you burn on a daily basis your body stores it as fat. Some of this fat for women goes to places where it is turned into cellulite. (a type of fat) for others it could be "brown fat", belly fat, back fat, breast fat.... heredity and genetics plays a roll in where your body tends to put it, not that you are destined to have an excess of it.
Drinking the right amount of water, eating a healthy, nutritious diet, and exercising on a regular basis to keep your body running at it's optimal and intended state of being are all great ways to prevent or reverse this effect.
We, as an entire collective, have fallen into a way of existing filled with poor/bad habits and negative mindsets which only perpetuate the problem.