21st Century India: 1.2 billion people have no toilet at home
Only 46.9% of the 246.6 million households have lavatories while 49.8% defecate in the open. The remaining 3.2% use public toilets.
Census 2011 data on houses, household amenities and assets reveal that 63.2% of homes have a telephone.
Analysts say the data show the complex contradictions of the Indian system.
They say the census reveals a country where millions have access to cutting-edge technology and consumer goods but a larger number of poor who lack access to even basic facilities.
About 77% of homes in the eastern state of Jharkhand have no toilet facilities, while the figure is 76.6% for Orissa and 75.8% in Bihar. All three are among India's poorest states with huge populations which live on less than a dollar a day.
"Open defecation continues to be a big concern for the country as almost half of the population do it," Registrar General and Census Commissioner C Chandramouli said while releasing the latest data.
"Cultural and traditional reasons and a lack of education are the prime reasons for this unhygienic practice. We have to do a lot in these fronts," he said.
The data also reveal that Indians now largely live in nuclear families with 70% of homes consisting of only one couple - a dramatic change in a country where joint families were always the norm.
The census figures also show changes in how people access information and entertainment.
More than half the population - 53.2% - have a mobile phone.
There has been a 16% rise in the number of homes with television sets, while the use of radios has declined by 15%.
The data show that 47.2% of households have a television while only 19.9% have a radio.
And the reach of computers with internet access is still minuscule, with only 3.1% of the population connected.