India is a relatively young country. Half of India's population is under the age of 30, making it a far younger country than its European, North American and East Asian counterparts. The median American or Chinese person, for instance, is over a decade older than the median Indian.
This is a result of India's historically higher fertility rates; until 2010, fertility in India was higher than in the world on average.
However, this is changing. With falling fertility, the relative share of children in India's population is falling, and the country is ageing. From the early 1970s, the share of children (aged 0-14) in the population began to decline, and from the 1980s, the share of young adults (14-29 year-olds) in the population began to fall.
Age-groups in Indian states
Within India, there are wide variations between states in the ages of their populations.[1]
States in India's centre-north have historically been poorer with lower levels of education, as a result of which fertility is higher in these states. Relatively high birth rates - meaning that a larger number of children are born every year - makes these states, on average, relatively younger. India's richer southern and western states, meanwhile, have lower fertility rates and are, as a result, ageing rapidly.
As of 2026, 24% of India's population was under the age of 15, 65% were between 15 and 59 years of age, and the remaining 11% were over the age of 60. However the size of child population is much larger in India's poorer states; over 30% of the population in Bihar, for instance, is under the age of 15.
Conversely, the richer southern states have a significantly larger elderly population. As of 2026, 19% of Kerala's population, for instance, was over the age of 60. This means that Kerala had over twice the share of elderly people in its population that Bihar or Uttar Pradesh had.
Working-age populations
Economists and policy planners are particularly interested in the population aged 15-59, which is known as the working-age population by some definitions.
Across the country, the number of children born every year has begun to fall in absolute terms - fewer children are born every year than the previous year. Ultimately, this will mean that the working-age population will begin to fall in India, and in every state.
Since the child population began to fall relatively later in the north-central and central-eastern states, their working-age populations are still growing. In the southern states, on the other hand, the working-age populations are either stagnating or shrinking.
Population projections made based on the 2011 Census have Tamil Nadu's and Kerala's working-age populations peaking in 2026, following which they are projected to decline in absolute size. In Uttar Pradesh and Bihar, on the other hand, the working-age population is projected to continue to grow beyond 2036, the furthest year for which there are population projections.
Median age in Indian states
As a result of these significant differences in the age structures of Indian states, there is a large difference in the median ages of the populations of these states. The median age is the mid-point of the population's ages: half the population is below this age, and half above.
As of 2021, Kerala was India's oldest state, and Bihar the youngest. But by 2031, Tamil Nadu is projected to be India's oldest state with a median age of nearly 40 years. The median person in Tamil Nadu or Kerala is over a decade older than the median person in Bihar or Uttar Pradesh, and the gap between the states will grow slightly over the 25-year period for which this data is projected.
Dependency ratios
One key indicator tracked by demographers and economists is the dependency ratio - the ratio of dependents (those who cannot work because they are either children or the elderly) to the working-age population. In states or countries with a higher dependency ratio, there is a greater financial burden on the working-age population and the state to provide welfare.
With India's child population shrinking, the country's dependency ratio has been declining. By 2026, India's dependency ratio is projected to be 543, meaning that there will be 543 children (aged 0-14) and elderly people (aged 60+) for every 1,000 working-age people (aged 15-59).
However, this is now set to change. With the elderly population growing, India's dependency ratio is projected to rise sometime over the next decade, for the first time since the early 1950s.
However this change in dependency ratios looks very different across India's states.
Since the northern and eastern states are seeing a gradual ageing with birth rates now declining, their dependency ratios are poised to fall, as the working-age population grows and is more able to support dependents. However, the southern and western states will see their dependency ratios rise steadily as their populations age, and their workforces shrink.
Across the country, the same forces of declining child populations and growing elderly populations are playing out. However the differences in the timings of these changes between India's richer and poorer states means that the age distribution, both now and for the future, look very different depending on where in the country you are standing.
[1] In the absence of a Census since 2011, data beyond 2011 comes from projections made by the Registrar General of India, based on the 2011 Census. Population projections have their shortcomings, which we have written about here.
