Since the end of the Second World War, there has been a spectacular progress in the field of population studies. A noteworthy feature of this development was the interest in the study of population created in underdeveloped countries like India, Pakistan, the Philippines, Sri Lanka, etc.
Two important developments after the Second World War were responsible for this interest and for widening the scope of population research.
The rapid decline in the mortality of the low-income countries was the first such development, the second being the political emancipation of several Afro-Asian countries which, till then, had been under the colonial rule of some European country or the other.
With independence came raised aspirations and hopes for the removal of poverty and for raising the standard of living of the people and thus ensuring for them a better quality of life.
Thus, a new era of planning for development dawned in these countries and terms such as “economic planning,” “planning for development,” “five-year plans,” etc., came to be widely used.
The planners of these underdeveloped countries, while preparing plans for social and economic development, realised that an unprecedented fall in death rates arising out of the implementation of public health programmes and successful campaigns against communicable diseases had been responsible for accelerating the rate of population growth because birth rates had continued to remain unaffected.
It is worth noting that while the population of developing countries went up at the rate of 0.8 per cent during the period 1900-1950, it rose by 2.2 per cent during the period 1950-1970.
It is also worth nothing that while the average death rate in developing countries was 32 per thousand populations per year during the period 1900-50, it was 17 for the period 1960-70.
The rates of growth of population during the period 1950-70 were also spectacular, specially in developing countries. For instance, the rate of population growth in India during 1931-41 was 14.23 per cent whereas it was 21.64 during 1961-71.
These facts and figures clearly explain why it was not surprising that attention was drawn to the rapidly increasing rates of population growth and why the size and structure of the population were recognised as important factors in development planning.
It was also recognised that the rapidly growing population would adversely affect economic and social progress as well as efforts at improving the levels of living. Alternative plans for curbing the rate of population growth were therefore adopted.
In the “development decades” of 1960 and 1970, several nations, after surveying their present and future population situations, adopted specific population policies and family planning programmes.
Gradually, a wealth of new demographic data became available for many of the newly independent countries.
As realisation grew amongst planners, policy-makers and administrators of these countries that they required information on various aspects of life for preparing development plans, the importance of census and sample surveys as sources of data on various socio-economic and demographic aspects was accepted.
Even those countries, which did not have a regular census, undertook demographic sample surveys. The United Nations helped several countries to introduce systems of vital registration and to conduct sample surveys.