“Needs” mean something without which anyone can’t survive, which is common to all the people on earth. For example, food, water and safe sleeping station. “Wants” and “demands” are different. If it is less than all people, it is a want or a demand. We tend to use the word “demand”, when it involves a large group. It is very much related to the theory of capitalism vs communism.
When I was living in the USA, three words – need, want, and demand are all synonyms. Whatever people want is what they need, and they use them interchangeably. I’m very nervous with that. Needs are not wants, and wants are not demands. Those three words have quite different emphasis in meaning. But USA has much influence by corporations that think there are demands whatever they make. People don’t know what is a difference between what a need is and what a want is. If I want a car, then I need a car. Many things US have created are useful to people, useful to all people or most people or reasonable people, and a few are for a market of demand. I say no car is a need for people, but is a want. It is a meaning of transport, but not all people need a transport. It is a conditional want. 160301