In India, the population census is conducted at regular intervals. After how many years is the census of population normally carried out?

Introduction / Context:
The population census is one of the most important statistical exercises conducted by the Government of India. It provides detailed information on population size, distribution, literacy, occupation, and many other socio economic characteristics. For competitive exams, knowing the frequency of the census is a basic fact that often appears in questions on Indian polity and economy. This question asks how often the population census is normally conducted.

Given Data / Assumptions:

• We are concerned with the official population census conducted by the Government of India.
• Four possible intervals are given: 2 years, 5 years, 7 years, and 10 years.
• We assume the standard pattern that has been followed for many decades, where a census is taken at regular intervals across the entire country.

Concept / Approach:
In India, the census is conducted every ten years. It is known as a decennial census. The first complete modern census was conducted in 1881 and since then, with very few exceptions, the census has been conducted at ten year intervals. This regularity allows comparison of population data across time and helps in planning policies and programmes. Therefore, the correct answer among the given options is a ten year interval.

Step-by-Step Solution:
Step 1: Recall that major census years in India include 1951, 1961, 1971, 1981, 1991, 2001 and 2011.Step 2: Note that the difference between each of these years is ten years, which indicates a decennial pattern.Step 3: The census is a large and complex exercise that covers the entire population, which makes it impractical to conduct every few years.Step 4: The recognised international practice in many countries, including India, is to conduct the census every ten years.Step 5: Therefore, the correct interval among the options given is 10 years.

Verification / Alternative check:
Official documents from the Census of India clearly describe the census as a decennial exercise. Historical records show data for census years spaced ten years apart. Exam preparation books on Indian economy and polity also state that the census is held every ten years. This repeated confirmation from multiple sources verifies that a ten year interval is correct.

Why Other Options Are Wrong:
2 years: Conducting a full population census every two years would be extremely costly and is not the practice followed in India.

5 years: Although some sample surveys are conducted more frequently, the full census is not a five year exercise.

7 years: There is no standard practice of conducting the census every seven years in India.

Common Pitfalls:
Some candidates confuse the census with other surveys such as the National Sample Survey or the National Family Health Survey, which may be held more frequently. Others mistakenly think that because many plans or schemes are five year based, the census might also follow a five year cycle. Remembering the list of census years and recognising the ten year gap helps avoid such confusion.

Final Answer:
The population census in India is normally conducted every 10 years.