At the last Census in 2011, Chennai district had 989 women for every 1,000 men, slightly below the Tamil Nadu figure of 996. Among children up to six years old, though, the city did better than the state: the provisional count showed 964 girls per 1,000 boys in Chennai against 946 for Tamil Nadu as a whole.
Those two ratios, plus the share of older people, are the numbers that shape everything from school planning to geriatric wards. Census 2011 is still the only complete count, so this piece sets out what it measured, what the later National Family Health Survey (NFHS) suggests, and how fast the state is ageing according to official projections.
The Census 2011 baseline
The state’s Statistical Hand Book reproduces the final 2011 totals: 23,35,844 men and 23,10,888 women in Chennai district, which then covered the old 175 sq km city. The Tamil Nadu Census directorate’s provisional population totals add the child figures. Provisional numbers differ slightly from the final ones, so the table labels each.
| Indicator | Chennai | Tamil Nadu | Year and status |
|---|---|---|---|
| Sex ratio (women per 1,000 men) | 989 | 996 | Census 2011, final |
| Sex ratio (women per 1,000 men) | 986 | 995 | Census 2011, provisional |
| Children aged 0-6 | 4,18,541 | 68,94,821 | Census 2011, provisional |
| Child sex ratio, 0-6 (girls per 1,000 boys) | 964 | 946 | Census 2011, provisional |
| Child sex ratio, urban Tamil Nadu | Not applicable | 957 | Census 2011, provisional |
Chennai was counted as entirely urban, so its total and urban figures are the same. Its child sex ratio was higher than the average for urban Tamil Nadu as well as for the state overall.
What NFHS-5 says about Chennai
The National Family Health Survey is a sample survey, not a head count, but it is the only recent official source with a Chennai district sheet. The NFHS-5 compendium for Tamil Nadu, published by the International Institute for Population Sciences for the Union health ministry, covers fieldwork in 2019-21.
| NFHS indicator, Chennai | NFHS-4 (2015-16) | NFHS-5 (2019-21) |
|---|---|---|
| Sex ratio of household population (women per 1,000 men) | 1,032 | 1,037 |
| Sex ratio at birth, children born in last five years | Not used here | 859 |
| Population below age 15 | 22.2% | 18.0% |
| Tamil Nadu: sex ratio of household population | 1,033 | 1,088 |
| Tamil Nadu: sex ratio at birth, last five years | 954 | 878 |
Read these with care. The Chennai sheet is based on 743 households, so a sex ratio at birth built from a few hundred recent births swings widely between rounds; the NFHS-4 Chennai value in the compendium is clearly a misprint and is left out. The household sex ratio also counts only people living in the households surveyed, which tends to under-represent working men in hostels, mansions and company quarters. Census 2027 will give the first full count since 2011.
The steadier signal is age. The share of Chennai’s surveyed population under 15 fell from 22.2% to 18.0% between the two rounds, consistent with the falling birth numbers in the city’s civil registration data.
How fast the state is ageing
Census 2011 counted 75,09,758 people aged 60 and above in Tamil Nadu, according to the age tables in the state handbook, about 10.4% of the population. Women outnumbered men in that group, 38,48,532 to 36,61,226.
The Union statistics ministry’s report Elderly in India 2021, as reported by ThePrint, projected that people aged 60 and over would make up 13.6% of Tamil Nadu’s population in 2021 and 18.2% in 2031. Only Kerala was projected to be older, at 16.5% and 20.9%. Nationally, the report projected about 13.8 crore elderly in 2021, rising to 19.4 crore by 2031.
| Tamil Nadu, population aged 60+ | Share | Source and year |
|---|---|---|
| 2011 | About 10.4% | Census 2011 age tables |
| 2021 | 13.6% (projected) | Elderly in India 2021 |
| 2031 | 18.2% (projected) | Elderly in India 2021 |
No official source checked for this article gives a separate count of Chennai district’s elderly, so we do not estimate one here.
Why these ratios matter locally
- Schools: a shrinking under-15 share means fewer new entrants in some Corporation and government schools, while demand shifts to suburbs where young families move.
- Health services: a state heading towards nearly one in five people over 60 by 2031 needs more geriatric outpatient clinics, home care and pension administration.
- Safety and transport: a near-balanced adult sex ratio means women are roughly half of all commuters, a basic input for bus, metro and street-lighting plans.
- Child sex ratio: the 2011 Chennai figure of 964 is a benchmark that Census 2027 will test; sample-survey dips are a reason to watch, not proof of a trend.
Quick answers
What is Chennai’s sex ratio?
989 women per 1,000 men in the final Census 2011 count. NFHS-5 (2019-21) recorded 1,037 in its sample of Chennai households.
What is Chennai’s child sex ratio?
964 girls per 1,000 boys aged 0-6 in the provisional Census 2011 totals, higher than the state’s 946.
How many elderly people live in Tamil Nadu?
Census 2011 counted about 75.1 lakh people aged 60 and above. Official projections put the elderly share at 18.2% by 2031.
When will new figures come?
From Census 2027, which will be the first complete count since 2011.
Information checked against official sources on 18 October 2026. Fees, dates and rules can change; confirm on the linked official pages before acting.
Sources
- Statistical Hand Book of Tamil Nadu, Area and Population (Department of Economics and Statistics, Government of Tamil Nadu)
- Census of India 2011, Provisional Population Totals Paper 2, Tamil Nadu (Directorate of Census Operations, Tamil Nadu)
- Compendium of NFHS-5 (2019-21) State and District Fact Sheets, Tamil Nadu (IIPS and Ministry of Health and Family Welfare, via OpenCity)
- India’s elderly population to rise 41% over next decade, govt report (ThePrint, August 2021)
