The definition of poor may change person to person, perspective is different. 
poverty is a widespread social evil in underdeveloped countries like in Asia and Africa. There is no standard definition of poverty for all the countries. The meaning of poverty differs from country to country.

WHO ARE THE POOR?

It will be really interesting to know who the poor people in India are or to which class they belong. We can see a number of people around us, if we go to remote areas and J.J. Colonies in the urban sector. The major chunk of the poor people in rural areas generally belong to the following principal categories – the landless labourers, the small and marginal farmers, the agricultural and casual labourers, the rural artisans, the tribals and disabled persons. Similarly in urban sector, most of the poor people are among the casual workers, daily wage workers working at construction sites, domestic servants, rickshaw pullers, Wenders, Street cobblers, child workers working in canteens and dhabas, beggars and the people living in jhuggis.

There are families who do not get enough food to feed their members. We can see people who do not have enough clothes to wear. We come across a number of people who do not have house and hence sleep under the open sky. We can see such poor people in a very large number in our country. In fact, every fourth person in India is poor.

in independent India, the concept of poverty line is based on calorie intake. It is found that in India the average calorie requirement of an average man is to have 2400 cal per day in rural and 2100 cal per day in urban sector. 
poverty line does is defined as the midpoint of the monthly per capita expenditure class, having a daily calorie intake of 2400 cal per person in rural areas and 2100 cal per person in urban areas.

CAUSES OF POVERTY!

when the large number of people in a country are entangled in poverty, it adversely affects the economy.

There are a number of reasons which are responsible for the problem of poverty in India these reasons can be economic factors and non-economic factors.

1.ECONOMIC FACTORS

There are many economic factors that are the major causes of poverty in India. Major of them are listed below.

a) under utilisation of natural resources.

b) Low level of technology and backwardness in agriculture.

c) widespread unemployment.

d) The vicious circle of poverty and inequalities.

2.NON- ECONOMIC FACTORS 

there are so many non-economic factors that led to the cause of poverty in India. Some of these are mentioned below.
a) Legacy or rule of Britishers

b) rapid or continuous rise in population

c) social factors like illiteracy ignorance backwardness or outdated anti-development social structure.