What is the concept of poverty line? How it varies with time and place?

(i) A common method used to measure poverty is based on the income or consumption level.
(ii) A person is considered poor, if his or her income or consumption level falls below a given ‘minimum level’ necessary to fulfil basic needs.
(iii) What is necessary to satisfy basic needs is different at different times and
in different countries.
(iv) There fore, poverty line may vary with time and place. Each country uses an imaginary line that is considered appropriate for its existing level of development and its accepted minimum social norms.
(v) For example, a person not having a car in the US may be considered poor. In India, owing of a car is still considered a luxury.