In the Census of India 2001, the definition of urban area adopted is as follows:
a) All places with a municipality, corporation, cantonment board or Notified town area committee, etc.
b) A place satisfying the following three criteria simultaneously:
i) A minimum population of 5,000;
ii) At least 75 per cent of male working population engaged in Non-agricultural pursuits; and
iii) A density of population of at least 400 per sq. km. (1,000 per Sq. mile)

For identification of places which would qualify to be classified as ‘urban’ all villages, which, as per the 1991 Census had a population of 4,000 and above, a population density of 400 persons per sq. km. and having at least 75 per cent of male working population engaged in non-agricultural activity were considered.

To work out the proportion of male working population referred to at least 75 percent of male working population engaged in Non-agricultural pursuits, the data relating to male workers were taken into account.

Apart from these, the outgrowths (OGs) of cities and towns have also been treated as urban under ‘Urban Agglomerations’: Examples of out-growths are railway colonies, university campuses, port areas, military camps, etc. that may have come up near a statutory town or city but within the revenue limits of a villages or villages contiguous to the town or city. Each such individual area by itself may not satisfy the demographic criteria laid down at (b) above to qualify it to be treated as an independent urban unit but may deserve to be clubbed with the towns as a continuous urban spread. Thus, the town level data, wherever presented, also includes the data for outgrowths of such towns.

Towns with population of 1,00,000 and above are called cities.
The number of towns and cities has increased to 4378.

More than half of the world's population will be living in urban areas by 2008. Almost 180,000 people are added to the urban population each day. The world's cities are growing at an astronomical rate of one million people each week. Projections for the year 2025 show that more than two thirds of us will be city dwellers.

By 2030, it is expected that 60% of the world population will live in urban areas.

27.8% of India’s total population lives in urban areas. That means 285 million urban citizens, as many people as there are in the United States totally. Urban India is a study in contrasts: it contributes 60% of the country’s national income. But 76 million urban Indians live below the poverty line, 21% of the urban population lives in slums, and 60% work in the unorganized sector, without any kind of social security

1.1 Some Basic Facts of India’s Urbanisation: 2001
Total Urban population	285 million Percentage to total population of India (27.78) Percentage to world’s urban population (10.02) Percentage to Asia’s urban population (21.10) Larger than the total population of small countries like France, Germany Larger than the total population of big countries like Brazil, USA Larger than the total population of parts of continents like Eastern Africa, Western Asia, Western Europe Larger than the total population of the whole continent of Australia.
Total population of 35 million-plus cities	107.88 million Percentage to total urban population (37.8) These 35 cities belong to the large group of 206 million plus cities of Asia
Total population of 393 Class I cities including million-plus cities	195.95 million Percentage to total urban population (68.67)

The definition and methods of measuring poverty differ from country to country. In India it is based on a nationally desirable minimum level of consumption expenditure based on a standard balanced diet prescribed by the Nutrition Advisory Committee. In other words, any family who could not afford to buy a rudimentary food basket, which when consumed yielded a minimum level of calories, was considered poor.

According to an expert group of Planning Commission of India, the poverty line is drawn with an intake of 2400 calories in rural areas and 2100 calories in urban areas. The person unable to get this minimum level of calories is considered as being below the poverty line.

However over the time the methodology for estimating poverty has been modified for updating the urban poverty line on the basis of Consumer Price Index for Industrial Workers alone instead of average of Consumer Price Index of Industrial Workers and Consumer Price Index of Urban Non-manual Employees (CPI-UNME).

Most commonly the urban poor are defined in terms of ‘income poverty’, however, urban poverty is a multidimensional phenomenon. ‘Poor People’, in cities suffer from various different forms of deprivation i.e. health poverty, education poverty, tenure insecurity, personal insecurity and disempowerment, in addition to income poverty.

Urban poverty is often characterized by cumulative deprivations, one of which leads to another. So the urban poor suffer from different types of deprivations.

The different dimensions of urban poverty are: income; education; tenure; insecurity; personal insecurity and disempowerment.

Source: Handbook of urbanization in India