The population of India as recorded at each decenial census from 1901 has grown steadily except for a decrease during 1911-21. The population of India, at the turn of the Twentieth century was around 238.4 million. The population of India as recorded at each decennial census from 1901 has grown steadily except for a decrease during 1911-21.
The percent decadal growth of population in the inter-censal period 1901- 2001 varies from a low of 9.42 in Kerala to a very high 64.41 in Nagaland. Delhi with 46.31 percent, Chandigarh with 40.33 percent and Sikkim with 32.98 percent registered very high growth rates. In addition to Kerala, Tamil Nadu and Andhra Pradesh registered low growth rates during 1991-2001. The percent decadal growth rate has declined during the census 1901-2001 as compared to the previous census decade, in all the States/Union territories except Haryana, Uttar Pradesh, Bihar, Sikkim, Nagaland, Manipur, Gujarat, Daman and Diu and Dadra and Nagar Haveli.
For the purpose of census 2001, a person aged seven and above, who can read and write with the understanding in any language, is treated as literate. The literacy rate in the country is 65.38 per cent, 75.85 for males and 54.16 for females. Kerala retained its position by being on top with a 90.92 percent literacy rate, closely followed by Mizoram (88.49 percent) and Lakshadweep (87.52 per cent). Bihar with a literacy rate of 47.53 percent ranks last in the country preceded by Jharkhand (54.13) and Jammu and Kashmir (54.46 percent).
One of the important indices of population concentration is the density of population. It is defined as the number of persons per square km. The population density has gone up from 267 persons in 1991 to 324 persons in 2001. In 1901 it was 77 persons.
Sex ratio is defined as the number of females per thousand males. In India, it has generally been adverse to women. The ratio has also declined over the years except in 1981 when it slightly improved to 934 from 927. In 2001 it was 933.