Reading a Block's Census: Density, Growth and a Sex Ratio That Argues Back
A student in a north Bihar community-development block compiles two data sets for a school project. In 2011 the block had 2,40,000 people spread over 380 km²; a 2021 house-listing-based estimate puts it at 3,10,000. The sex ratio is 902 females per 1,000 males, and the child sex ratio (0–6 years) is 878. Literacy is 54 per cent overall - 63 per cent for males, 44 per cent for females. Eighty-six per cent of the people live in villages; only 34 per cent of the population is counted as workers, and 62 per cent of those workers are main workers. Local bus and rail enquiries suggest about 18,000 men aged 15–35 are absent from the block for most of the year, working in Punjab, Gujarat and Delhi. The teacher says the low sex ratio is simply 'because our men go out to work'. The student is not convinced, and has to present the block's demographic profile at a district exhibition.
1. Calculate the 2011 and 2021 population densities and the decadal growth rate. What do these figures suggest about the block's position in the demographic transition, and what caution must accompany them?
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Density is population divided by area: 2,40,000 ÷ 380 = 632 persons per km² in 2011; 3,10,000 ÷ 380 = 816 per km² in 2021. Growth = (3,10,000 − 2,40,000) ÷ 2,40,000 × 100 = 29.2 per cent over the decade, roughly 2.6 per cent a year.
Reasoning. A density of 816 is well below Bihar's 1,106 (2011), but that is partly an artefact: a large share of the block is flood-prone or otherwise uncultivated, so physiological density (people per hectare of net sown area) is more revealing here than arithmetic density.
A 29 per cent decadal growth is above the state's 25.4 per cent for 2001–11. With literacy at 54 per cent and a very young age structure, the block sits in the late-expanding stage: death rates have already fallen, birth rates are falling but slowly, and the large cohort of children guarantees further growth through population momentum even if fertility drops tomorrow.
Caution: the 2021 figure is a projection from house-listing, not a census count, and migration distorts both numerator and denominator. Report 816 as approximate, and always state the source and year in the practical file.
2. Evaluate the teacher's explanation. Give two alternative explanations that fit the numbers better.
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The teacher has confused an effect with a cause. The sex ratio is females per 1,000 males; if 18,000 young men are working outside the block, they are subtracted from the resident male count, so the recorded ratio should be higher than the true resident ratio, not lower. An observed 902 in spite of male out-migration means the underlying deficit is even larger.
Better explanations, in order of weight:
- A deficit created before and during childhood. The child sex ratio of 878 is the diagnostic figure. Son preference expressed through sex-selective abortion, plus poorer nutrition, immunisation and treatment-seeking for girls, lowers the number of females long before anyone migrates.
- Measurement effects. Women may be under-enumerated or reported in a husband's village, and seasonal in-migration of male harvest labour (the opposite flow to the one the teacher cites) inflates the male count in some months.
A defensible answer states the arithmetic first, then uses the child sex ratio to locate the problem in the birth-to-adolescence years, and only then mentions data quality.
3. Recommend two interventions, rank them, and explain the reasoning behind the ranking.
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First: girls' secondary schooling - scholarships, free cycles, a girls' toilet in every high school, and safe transport. The female literacy gap is 19 points (63 vs 44). Schooling is the one lever that works on all the causes at once: it delays marriage, improves health-seeking, raises female work participation, and erodes son preference across a generation. It is slow, but self-sustaining.
Second: a birth-and-survival incentive with public monitoring - a conditional transfer at the birth and schooling of a girl, combined with the panchayat publishing quarterly births by sex and the child sex ratio for each ward. The 878 figure is the most urgent number, and visibility plus community pressure acts faster than schooling.
Ranking logic: the transfer buys speed on the acute indicator; education buys durability on the structural one. Do both, but do not fund a statue or a gate - visible assets change no indicator.
A third, enabling step: train and deploy female enumerators, because a distorted count will misdirect any scheme built on it. Note that remittance policy is a separate welfare question - it does not move the sex ratio.