An informal settlement is like playing pretend in a fort that you made with your friends, but instead of a fort, it's a community of people who made a home in a piece of land where they were not really supposed to live.
When some people don't have a lot of money to pay for a house or apartment, they might go to a place where other people have set up makeshift homes. This could be a lot, a field, or even a street. These places may not have all the things that normal neighborhoods have, like electricity or clean water, but people still choose to live there because it's a better option than being homeless.
The people who live in an informal settlement usually create their own homes out of whatever materials they can find, like cardboard, tin, or plastic. These homes may not be very strong, and they might not have bathrooms or kitchens. It's a very different way of living compared to what you might be used to.
Informal settlements can be found in many places around the world, and they're often called different things. In some places, they're known as shantytowns, in others, they're called squatter settlements. No matter what they're called, they're all places where people have made their homes in a way that's different from what most people are used to.