In India, population density is officially defined as the number of persons living per which unit of area?

Introduction / Context:
This question is from Indian geography and demography. Population density is a basic indicator used in census reports and economic surveys. It shows how crowded or sparsely populated an area is. Different countries may use different units, so it is important to know what unit India uses in its official statistics.

Given Data / Assumptions:

• The term is population density in the Indian context.
• We are asked about the unit of area used in the definition.
• Options include per square mile, per square kilometre, per lakh square mile, per lakh square kilometre, and per hectare.

Concept / Approach:
Population density is calculated as total population divided by area. In India, as in many other countries following the metric system, the area is measured in square kilometres. Census documents routinely express density as number of persons per square kilometre. Some older texts or international comparisons sometimes use square miles, but that is not the standard unit in Indian official usage.

Step-by-Step Solution:
Step 1: Recall that India uses the metric system officially, which favours kilometres rather than miles.Step 2: Population density figures in Indian census reports are given as persons per square kilometre.Step 3: Units like per lakh square kilometre or per hectare are not standard for expressing national population density.Step 4: Therefore, the correct unit is per square kilometre.Step 5: Select the option that states per square kilometre.

Verification / Alternative check:
Think of commonly quoted figures such as Indias population density being over three hundred or four hundred persons per square kilometre in some census years. If the unit were per square mile or per lakh square kilometre, the numbers would look drastically different and would not match what is seen in textbooks or government reports. This confirms that per square kilometre is the correct unit.

Why Other Options Are Wrong:
Per square mile is a unit used in some non metric systems, but Indian census reports do not use it as the primary unit. Per lakh square mile or per lakh square kilometre are unusual and would produce very small numerical values, which are not the standard representation. Per hectare is often used for agricultural productivity measures such as yield per hectare, not for national population density.

Common Pitfalls:
Students sometimes see data in foreign publications that use square miles and get confused about what India uses. Another pitfall is mixing up units used for different indicators, such as hectares for land productivity and square kilometres for population. During revision, it is useful to make a small note that population density in Indian official documents is always expressed as persons per square kilometre.

Final Answer:
In India, population density is defined as the number of persons living per square kilometre of area.