We've made some incredible technological space advancements particularly with our low orbit and colonization of it so to speak. Our Low orbit contains all of our satellites and various stations that power most of our modern day communications.
With this has come a pending issue and has created a massive amount of debris which can account for now over 100million pieces of "space junk" floating in our low orbit.
Here is a great video which shows in greater detail exactly the problem we've created.
At some point our human race will need to effectively clean this pollution or it very well could severely hamper our future cosmos exploration.