Particular Environment and Climate
After all, everyone knows that Australia’s environment is covered in a group of massive deserts, not to mention many dangerous animals and insects.
Australia’s population density is low because most of the country’s geographic perspective is desert (also known as the outback) and presents extremely difficult living conditions. So, while Australia’s major cities have over-crowded comparable to the rest of the Western world when you take into consideration all the empty space in the middle, you get a low overall population density.
Another fact is Australia is close to the frozen continent of Antarctica, and the western side is mixed up with a cold ocean which would lead to not providing enough heat. There is also a water shortage problem where Australia’s population more than 25 million but the water supply for only 12–15 million. How do 25 million survive with the water for far fewer? They’ve tapped aquifers that took thousands of years to fill, and in some cases made them useless in under 200 years of that area’s underground water being utilized.