The year 1921 is regarded as the defining year or the 'Year of Great Divide' because prior to 1921, population growth in India was never consistent. India was in the first phase of demographic transition till 1921 that was characterized by high birth rate and high death rate. It implies low survival rate (or low life expectancy), which was nearly 8 per thousand per annual. Therefore, the period before 1921 witnessed stagnant population growth rate. After 1921, India's population growth never declined and showed a consistent upward trend.
