Life expectancy

Also called: Life expectancy at birth · Topic: Measuring Development: Income, HDI and Sustainability · NCERT: Class 10, Ch 1 "Development"; Class 11, Ch 1 "Indian Economy on the Eve of Independence"; Class 11, Ch 4 "Human Capital Formation in India"; Class 11, Ch 8 "Comparative Development Experiences of India and its Neighbours"

Meaning

Life expectancy at birth is the average number of years a newborn baby would live if today's death rates at each age stayed the same for its whole life. It is not a forecast of how long any one baby will actually live. It is a summary of the death rates a country has today.

It matters because it is the health dimension of the Human Development Index (HDI), the UNDP's index of health, education and income. It shows something income alone cannot: two countries can have the same per capita income and still differ a lot in how long their people live.

Explanation

How it works

• Start with the death rate at each age in a given year: babies, children, adults and the old.
• Imagine a newborn who faces these same death rates at every age, all through life.
• Work out how many years such a baby lives on average. That average is life expectancy at birth.
• A snapshot, not a prediction:
• It uses current death rates only.

• If health care improves later, babies born today will actually live longer than the figure says.

• It is not the "normal" age of death. A life expectancy of 32 years does not mean most adults died at 32. It means many babies and children died very young, and that pulled the average down.

Why infant and child deaths matter most

• A death at age 0 removes a whole lifetime from the average.
• A death at age 70 removes only a few years compared with the average.

• So saving babies raises life expectancy far more than saving the old.

• Worked example (hypothetical numbers): 5 babies are born in a village.

• One dies before the first birthday (age 0). The other four live to 70.
• Life expectancy = (0 + 70 + 70 + 70 + 70) ÷ 5 = 280 ÷ 5 = 56 years.
• Now the infant death is prevented and that child also lives to 70.
• Life expectancy = (70 × 5) ÷ 5 = 70 years.

• Preventing one infant death raised the average by 14 years.

• This is why the Infant Mortality Rate (IMR) (babies who die before their first birthday, per 1,000 live births) and life expectancy usually move in opposite directions.

What makes it rise or fall

• It rises with:
• clean water and sanitation, which mean fewer diarrhoea deaths;
• vaccination and institutional deliveries (births in hospitals or health centres);
• better nutrition and mothers' education;

• fewer maternal deaths (women dying from causes linked to pregnancy).

• It falls with: famine, epidemics, war, and gender discrimination in food and health care.

• Male versus female: women outliving men is the normal biological pattern. When men live longer, it points to discrimination against women and high maternal deaths.

In India

• Long-run trend (NCERT, Class 11, Table 4.1):

Period	Male	Female
Colonial India	about 32 years (overall)	—
1951	37.2	36.2
1981	54.1	54.7
1991	59.7	60.9
2001	63.9	66.9
2018-22	68.6	71.4

• Latest figure: the Human Development Report (HDR) 2025, using 2023 data, puts India's life expectancy at 72.0 years.
• Life expectancy nearly doubled between 1951 and 2018-22 for both men and women.
• The gender crossover:
• In 1951, men lived longer than women (37.2 vs 36.2). This reversed pattern reflected gender discrimination and high maternal deaths.
• By 1981, women had overtaken men (54.7 vs 54.1).

• In 2018-22, the gap was 71.4 (women) vs 68.6 (men), which is the normal pattern.

• What drove the rise: falling deaths among the young.

• IMR fell from about 218 (colonial period) to 146 (1951) and 28 (2018-22).
• The crude death rate fell from 25.1 (1951) to 6.0 (2018-22) per 1,000 people.
• IMR fell from 39 per 1,000 live births (2014) to 27 (2021), based on the Sample Registration System (SRS), the Registrar General's large sample survey of births and deaths [2].

• Between 1990 and 2023, India cut IMR by 71%, the Under-Five Mortality Rate (child deaths before age 5) by 78%, and the Neonatal Mortality Rate (baby deaths in the first 28 days) by 70% [2].

• Income vs longevity: real per capita income rose about 12 times (Rs 7,651 in 1951 → Rs 94,054 in 2018-22), while life expectancy nearly doubled.

Don't confuse with

• Infant Mortality Rate (IMR): IMR counts infant deaths per 1,000 live births in one year. Life expectancy is an average of years of life. IMR is one of the main inputs that pushes life expectancy up or down.
• Crude death rate (CDR): CDR = deaths per 1,000 people in a year. It ignores age structure, so a young country can have a low CDR even with weak health services. Life expectancy is built from death rates at each age, so the age mix of the population does not distort it.
• Life span / actual age at death: life expectancy is a snapshot of today's death rates, not a forecast. A low figure (about 32 in colonial India) mostly reflects many child deaths, not adults dying at 32.
• HDI: life expectancy is only the health dimension of the HDI. The HDI also includes education and income.

Prelims Hooks

• Definition: the average years a newborn would live if current age-wise death rates stayed the same. It is a snapshot, not a forecast.
• Life expectancy at birth is the health indicator in the UNDP's HDI. HDR 2025 (data year 2023) puts India at 72.0 years.
• NCERT Table 4.1: 1951 had 37.2 (M) and 36.2 (F). 2018-22 had 68.6 (M) and 71.4 (F). Colonial India had about 32 years.
• Trap, "which of the following is correct": in 1951, Indian men had a higher life expectancy than women. Women overtook men by 1981.
• Biggest single driver: falling infant and child mortality, because a death at age 0 removes a whole lifetime from the average.
• Trap: a low life expectancy does not mean most adults died at that age. It is pulled down by early-age deaths.

Mains Points

• Growth is not the same as health: per capita income rose about 12 times from 1951 to 2018-22, and life expectancy nearly doubled. Longevity depends on public provision (clean water, vaccination, institutional deliveries, female literacy), not on income alone. This follows Amartya Sen's capability view, which is the basis of the HDI. Kerala's strong public health system is the usual Indian example (GS-II/III).
• Gender lens: the 1951 pattern of men outliving women, and the later crossover by 1981, show how discrimination and maternal deaths shorten women's lives. Cutting maternal mortality and child deaths therefore directly raises life expectancy. Programmes on nutrition, sanitation (SBM-G) and tap water (Jal Jeevan Mission) all feed into this.
• Limits of the indicator: life expectancy counts years, not the quality of those years. Anaemia, stunting and the double burden of malnutrition can persist even as longevity rises. Policy should track life expectancy alongside IMR, MMR and nutrition data, and always name the data source (SRS, NFHS or HDR).

Related concepts

• Infant Mortality Rate
• Maternal mortality rate
• Mortality rate
• Undernourishment
• Body Mass Index
• Access to sanitation and drinking water

Read more

• Health and nutrition indicators: reading the numbers