Q.India’s population as per 2011 census is :
Concept understanding — Population Data Recall
Population Data Recall – From Intuition to Precision
Imagine you are a census officer. You have a massive list of every person in a city — their age, income, education. That complete list is your population data. Now, a researcher asks you: "What fraction of people in this city have a college degree?"
You could answer instantly: just count from your complete list. That is recall in the most literal sense — you already have all the data, so you simply retrieve the exact answer.
But in statistics and machine learning, "recall" means something more specific. It is not about having the data; it is about how well a method finds the relevant items from a larger set.
The Intuition: Did we catch everything we should have?
Think of a medical test for a disease. Among 100 sick people, the test correctly identifies 90 of them as sick. The test recalled 90 out of 100 sick people — it "remembered" to flag them. The 10 it missed are dangerous failures.
That is the core idea: Recall measures the fraction of actual positives that your method correctly identifies. It answers: "Of all the things that should have been found, how many did we actually find?"
The Precise Statement
Let:
- True Positives (TP) = items correctly identified as positive (e.g., sick people correctly diagnosed)
- False Negatives (FN) = items that are positive but were missed (e.g., sick people told they are healthy)
Then:
Recall=TP+FNTP
The denominator TP+FN is simply the total number of actual positives in the population. So recall is a proportion between 0 and 1 (or 0% to 100%).
Why "Population Data Recall"?
The phrase Population Data Recall is not a standard term in most textbooks. It likely refers to one of two situations:
-
Recall computed on the entire population (not a sample). If you have the full census, your recall is the exact truth for that population — no sampling error.
-
A scenario where the "population" is the set of all relevant items (e.g., all sick people, all fraudulent transactions, all relevant documents). Recall tells you what fraction of that population your method successfully retrieved.
In either case, the formula is identical. The word "population" just emphasises that the denominator is the complete set of positives, not an estimate.
A Concrete Example
Suppose a spam filter processes 1000 emails. Among them, 200 are actually spam. The filter correctly flags 180 of those 200 as spam, but lets 20 spam emails through to your inbox.
- TP = 180
- FN = 20
- Total actual spam = 200
Recall=180+20180=200180=0.9=90%
The filter recalled 90% of the spam. The 10% it missed are the false negatives.
Common Mistake to Avoid
Do not confuse recall with precision. Precision asks: "Of everything I flagged as positive, how many were actually positive?" Recall asks: "Of all actual positives, how many did I flag?" They measure different things. A test that calls everyone "sick" has perfect recall (catches all sick people) but terrible precision (flags many healthy people too).
Why It Matters
Recall is critical when missing a positive is costly — medical diagnosis, fraud detection, airport security, search for a missing person. In such cases, you want recall as close to 100% as possible, even if it means some false alarms (lower precision).
In contrast, if false alarms are expensive (e.g., sending innocent people to jail), you might sacrifice recall for higher precision.
The One-Line Takeaway
Recall = fraction of actual positives that your method correctly identifies. It answers: "Did we catch everything we should have?"
The 2011 Census of India recorded the country's total population. Among the options given, the correct figure is the one that matches this official count.
- Option (a) 1028 million is close to India's population around the 2001 Census, not 2011.
- Options (b) 3182 million and (c) 3287 million are far too large — these numbers are closer to the entire population of the world, not just India.
- Option (d) 1210 million is the exact figure reported by the 2011 Census for India's total population.
India’s population as per the 2011 census is 1210 million, which corresponds to option (d).
India’s population as recorded in the 2011 Census was 1210 million (or 1.21 billion), making option (d) the correct answer.
The Census of India, conducted every ten years, is the most authoritative source for the country’s population data. The 2011 Census was the 15th such exercise and the largest census ever undertaken anywhere in the world at that time. It involved millions of enumerators visiting every household across the length and breadth of India, from the snow-capped Himalayas to the coastal villages of Kerala.
When the results were released, they showed that India’s population had crossed the 1.2 billion mark for the first time. The exact figure stood at 1,210,854,977 — which is commonly rounded and reported as 1210 million or 1.21 billion. This represented an increase of about 181 million people over the previous census of 2001, when the population was 1028 million.
Option (a) — 1028 million — is the 2001 Census figure, not the 2011 one. Options (b) and (c) — 3182 million and 3287 million — are far too large; they exceed even the current global population of India (which is about 1.4 billion as of 2024). So only option (d) matches the official 2011 Census count.
Why does this number matter? The 1210 million figure is not just a statistic — it tells a story of demographic transition. India had added roughly 181 million people in a decade, which is more than the entire population of many countries. Yet the growth rate had actually slowed compared to earlier decades, indicating that the country was moving towards a more stable population pattern. This data is crucial for planning everything from school seats and hospital beds to railway coaches and food grain production.
Always remember: the 2011 Census population of India is 1210 million (1.21 billion). The 2001 figure was 1028 million (1.02 billion). These two numbers are frequently tested in exams, and mixing them up is a common mistake.
In short, India’s population as per the 2011 Census is 1210 million (option d), which equals 1.21 billion people.
- CBSE 2026Set 64/1/11 markMCQQ.Study the following table carefully and answer Question Nos. 15 to 17. Most populous countries(Based on the table ‘Most populous countries’ in Question No. 15.) China and Brazil together account for what percentage of the world population ? (A) 17.88 (B) 17.58 (C) 19.88 (D) 19.58
Sr. No. Country Population % of world 1 India 1,425,775,850 17.4 2 China 1,409,670,000 17.2 3 United States of America 337,975,234 4.13 4 Indonesia 278,696,200 3.41 5 Pakistan 229,488,994 2.80 6 Nigeria 216,746,934 2.65 7 Brazil 219,277,799 2.68 8 Bangladesh 168,220,000 2.06 9 Mexico 128,271,248 1.57 ›Reveal solutionSolution
China and Brazil together account for 19.88% of the world population.
The table gives us the percentage share of each country in the world population. For China, that figure is 17.2%, and for Brazil, it is 2.68%. To find the combined share of these two countries, we simply add their individual percentages.
17.2 + 2.68 = 19.88
NoteThe population numbers themselves are not needed for this calculation — the percentages are already provided in the table. Adding them directly gives the answer.
ImportantA common mistake here is to misread Brazil's percentage as 2.65% (which belongs to Nigeria) or to accidentally add China's percentage to the wrong country. Always double-check which row corresponds to which country.
✓Final answerChina and Brazil together account for 19.88% of the world population, which corresponds to option (C).
- CBSE 2026Set 64/3/11 markMCQQ.During which one of the following decades, the population growth in India was negative ? (A) 1911 to 1921 (B) 1931 to 1941 (C) 1951 to 1961 (D) 1971 to 1981
›Reveal solutionSolution
India experienced negative population growth during the decade of 1911 to 1921, primarily due to the devastating influenza pandemic of 1918-1919. The correct option is (A).
Population growth refers to the change in the number of individuals in a population over a specific period. It is typically expressed as a percentage. When the number of deaths and emigration exceeds the number of births and immigration, a population experiences negative growth, meaning its total size decreases. Historically, major epidemics, famines, or wars have been the primary drivers of such declines.
-
Understanding Population Growth Trends in India:
India's population has generally shown a continuous upward trend throughout its recorded history. However, there is one notable exception where the population actually declined. This period is often referred to as the "Great Divide" in India's demographic history.
-
Identifying the Decade of Negative Growth:
Among the options provided, the decade from 1911 to 1921 stands out. During this ten-year period, India's population registered a decrease.
ImportantThe decade 1911-1921 is unique in India's demographic history for recording a negative population growth rate.
-
Reasons for Negative Growth (1911-1921):
The primary reason for this unprecedented decline was the severe influenza pandemic of 1918-1919, often called the "Spanish Flu." This global pandemic had a catastrophic impact on India, leading to millions of deaths. Estimates suggest that between 5% and 6% of India's total population perished during this epidemic. In addition to the influenza, the decade also saw the lingering effects of famines and other diseases, which further contributed to high mortality rates. The combination of these factors led to a situation where the death rate significantly surpassed the birth rate, resulting in an overall population reduction.
-
Population Growth in Other Decades:
- 1931 to 1941: India's population continued to grow, albeit at a moderate pace.
- 1951 to 1961: This decade marked the beginning of a period of rapid population growth in India, often termed the "population explosion," due to significant improvements in public health, disease control, and a consequent sharp decline in mortality rates, while birth rates remained high.
- 1971 to 1981: Population growth remained high during this decade, though efforts towards family planning were beginning to be implemented.
Therefore, the only decade among the given options that experienced negative population growth was 1911 to 1921.
✓Final answerThe population growth in India was negative during the decade (A) 1911 to 1921.
-
- CBSE 2026Set 64/3/11 markMCQQ.Which of the following set of states have the lowest percentage of urban population ? (A) Madhya Pradesh and Kerala (B) Punjab and Gujarat (C) Goa and Maharashtra (D) Bihar and Himachal Pradesh
›Reveal solutionSolution
Bihar and Himachal Pradesh record the lowest percentages of urban population among Indian states, reflecting their predominantly rural economies and settlement patterns.
India's urbanisation story is deeply uneven. While some states have transformed into industrial and service hubs with sprawling cities, others remain anchored to agriculture and village life. Understanding which states fall at the lower end of the urbanisation spectrum tells us as much about economic structure as it does about geography and history.
Bihar stands out as one of India's least urbanised states. Despite being densely populated, the overwhelming majority of its people live in villages. The state's economy remains heavily agrarian, with limited industrial growth and few large urban centres beyond Patna. Historical underinvestment in infrastructure and industry has meant that rural-to-urban migration within the state has been modest; instead, many Biharis migrate out to cities in other states for work.
Himachal Pradesh presents a different picture but arrives at a similar outcome. This hill state's terrain makes large-scale urbanisation difficult. Settlements are scattered across valleys and slopes, and the economy leans on agriculture, horticulture, and tourism rather than manufacturing or services that typically concentrate populations in cities. Shimla and a few other towns exist, but they house only a small fraction of the state's people.
Now contrast this with the other options. Punjab and Gujarat are both highly urbanised—Punjab through its prosperous towns and Gujarat through its industrial cities like Ahmedabad and Surat. Goa and Maharashtra are even more so; Mumbai alone makes Maharashtra one of India's most urban states, and Goa's compact geography and tourism economy have driven significant urban growth. Madhya Pradesh has moderate urbanisation, while Kerala, though densely populated, has a unique settlement pattern of continuous habitation that blurs rural-urban lines but still registers higher urban percentages than Bihar or Himachal Pradesh.
ImportantUrbanisation percentages reflect not just city size but economic structure. States with strong agricultural bases and limited industrial development tend to remain more rural.
The answer becomes clear when we recognise that Bihar and Himachal Pradesh share the twin characteristics of limited industrial bases and geographic or economic constraints on city growth.
✓Final answer(D) Bihar and Himachal Pradesh have the lowest percentage of urban population, shaped by their agrarian economies and, in Himachal's case, challenging mountainous terrain that limits large urban centres.
- CBSE 2025Set 64/1/11 markMCQQ.Choose the correct option to fill the blank : By 2050, the world population is estimated to live in urban areas is _____. (A) One fourth (B) Half (C) Two third (D) Three fourth
›Reveal solutionSolution
Urban migration trends project that by 2050 roughly two-thirds of the global population will reside in cities and urban areas, up from about 55% today.
Why urbanization projections matter
The movement of populations from rural to urban areas has been one of the defining demographic shifts of the past century. Understanding these trends helps governments plan infrastructure, housing, healthcare, and environmental policy. The United Nations tracks urbanization rates globally and produces long-term estimates based on current migration patterns, birth rates in urban versus rural areas, and economic development trajectories.
The urbanization trajectory
-
Historical baseline: In 1950, only about 30% of the world's population lived in urban areas. Cities were smaller, and most people worked in agriculture or rural industries.
-
Current state: As of the early 2020s, approximately 55–56% of the global population lives in urban areas. This represents a dramatic shift driven by industrialization, better urban employment opportunities, and rural-to-urban migration.
-
Projection to 2050: The UN Department of Economic and Social Affairs projects that urbanization will continue accelerating, particularly in Africa and Asia. By 2050, the urban share is expected to reach approximately 68%, or roughly two-thirds of the total population.
-
Regional variation: The pace differs by continent. Africa and Asia are urbanizing rapidly, while Europe and North America are already highly urbanized (80–85%) and will see slower growth.
NoteThe two-thirds figure (≈66–68%) is a rounded estimate. The exact percentage varies slightly depending on how "urban" is defined in different countries, but the consensus across major demographic studies converges on this range.
✓Final answerThe correct option is (C) Two third.
-
- CBSE 2023Set 64/1/11 markMCQQ.Which one of the following states has the highest population growth rate during 2001 to 2011 decade ? (A) Manipur (B) Nagaland (C) Mizoram (D) Sikkim
›Reveal solutionSolution
During the 2001-2011 decade, Manipur recorded the highest population growth rate among the given options, at 24.50%.
Understanding population growth rates is crucial for comprehending demographic shifts and their implications for development planning. A population growth rate indicates how quickly the number of individuals in a population is increasing or decreasing over a specific period, usually a decade in the context of Indian censuses. This metric helps policymakers allocate resources, plan infrastructure, and address social needs effectively.
The decade from 2001 to 2011 saw varying population growth trends across India's states and union territories. While some states experienced significant increases, others showed more moderate growth, and a few even registered a decline in population. The states listed in the question—Manipur, Nagaland, Mizoram, and Sikkim—are all located in the northeastern part of India, a region known for its diverse demographic patterns.
Let us examine the population growth rates for each of these states during the 2001-2011 decade:
- Manipur: This state recorded a population growth rate of 24.50%. This indicates a substantial increase in its population over the ten-year period.
- Nagaland: Uniquely among Indian states, Nagaland registered a negative population growth rate of -0.58% during this decade. This means its population actually decreased slightly between 2001 and 2011, a rare demographic phenomenon in India.
Note
A negative growth rate signifies a decline in the total population, which can be influenced by factors such as out-migration, lower birth rates, or higher death rates.
- Mizoram: Mizoram experienced a robust growth rate of 23.48%, indicating a significant expansion of its population.
- Sikkim: Sikkim's population grew at a rate of 12.89%, which is a moderate increase compared to Manipur and Mizoram, but still a positive growth.
Comparing these figures, Manipur's growth rate of 24.50% stands out as the highest among the four states provided. While Mizoram also showed strong growth, Manipur's rate was marginally higher. Nagaland's negative growth rate makes it an outlier, highlighting the diverse demographic trajectories within the region.
ImportantPopulation growth rates are not merely numbers; they reflect complex socio-economic and environmental dynamics, including birth rates, death rates, and migration patterns, all of which have profound impacts on a region's future.
✓Final answerAmong the given options, Manipur had the highest population growth rate of 24.50% during the 2001 to 2011 decade.
🎓Unlock everything free for 14 days
- ✓Full step-by-step solutions
- ✓Concept-first explanations
- ✓Methods, shortcuts & mistakes
- ✓PYQ mapping + timed mock tests
Full access for 14 days. No credit card required.