ELI5: Explain Like I'm 5

Population ageing

Population ageing is when there are more older people, who are usually over 65, than younger people in a population. This is usually because people are living longer because of advances in health and technology. This means that people are having fewer children and so there are fewer young people, but more older people. This can be a problem because it means there are not enough young people to take care of the older people.