The 2001 Census of India was the 14th in a series of censuses held in India every decade since 1871.

India is the second most populous country in the world, with over 1.277 billion people (2015), more than a sixth of the world's population. Already containing 17.5% of the world's population, India is projected to be the world's most populous country by 2022, surpassing China, its population reaching 1.6 billion by 2050. Its population growth rate is 1.2%, ranking 94th in the world in 2013. The Indian population had reached the billion mark by 1998.