The correct answer is: Every 10 years.
The Census of India is a decennial census of India, conducted by the Office of the Registrar General and Census Commissioner, India, under the Ministry of Home Affairs. The first census was conducted in 1872, and the most recent census was conducted in 2021. The census is used to collect data on the population of India, including age, sex, religion, language, literacy, and occupation. The data collected by the census is used to plan for development and to monitor the progress of development.
The census is conducted every 10 years because it is a time-consuming and expensive process. It takes several years to prepare for the census, and it takes several more years to analyze the data and publish the results. The census is also a very important process, and it is important to ensure that it is conducted accurately and efficiently.
The other options are incorrect because they are not the frequency at which the Census of India is conducted. The Census of India is not conducted every 5 years, annually, or whenever the government feels the need.