Migration in Demography: Internal and International Movements

Every ten years, when the Census counts India’s population, three numbers matter: how many people were born, how many died, and how many simply moved. That third number rarely gets the attention it deserves, yet it reshapes cities, empties villages, and quietly redraws the map of where India’s workforce actually lives. This is migration, and understanding it is central to understanding Indian demography.

Migration as the third demographic determinant 🔗

Population change is usually explained through fertility and mortality, but demographers treat migration as an equally important, and far more unpredictable, third factor. Unlike births and deaths, migration does not change the size of a country’s total population on its own; it changes where that population lives, and how it is distributed across regions. Migration is closely tied to urbanisation, economic development, and the broader demographic transition a country is going through, and it has a unique capacity to transform the size, composition, and spread of national populations over time, as researchers at the International Institute for Population Sciences have documented.

Demographers split migration into two broad categories based on whether a national border is crossed. Movement within a country’s own boundaries is called internal migration, while movement across international borders is called international migration. Both types affect population composition, but they do so at very different scales and with very different policy implications.

Internal migration: on the move within India 🔗

Internal migration is far larger in scale than most people assume. When someone moves into a particular state or district, they are counted as an in-migrant for that region. When they leave a region, they are counted as an out-migrant from it. The same person can be both, simply depending on which end of the journey you are looking at.

The scale of movement 🔗

According to the 2011 Census, the most recent full count available, India had 45.6 crore internal and international migrants, making up 38 percent of the total population, up from 31 percent in 2001. Strikingly, between 2001 and 2011 the overall population grew by 18 percent, while the number of migrants grew by 45 percent, showing that mobility was increasing far faster than population itself. Of all these migrants, 99 percent moved within the country, and only 1 percent crossed an international border, which tells you just how dominant internal movement is in the Indian context.

Where people go, and why 🔗

Internal migration in India is not random. Certain states consistently send people out, and others consistently pull them in. As per Census data, Uttar Pradesh and Bihar have long been the largest sources of inter-state migrants, while Maharashtra and Delhi have been the largest receivers, with around 83 lakh residents of Uttar Pradesh and 63 lakh residents of Bihar having moved to other states by 2011. A government review of internal migration patterns by the Economic Advisory Council to the Prime Minister similarly tracks these state-to-state flows, showing how migrant labour concentrates in a handful of industrial and metropolitan destinations.

Reasons for moving differ sharply by sex. Marriage and family were behind roughly 70 percent of intra-state migration, but this figure hides a big gender gap: 83 percent of women who moved within a state did so for marriage or family reasons, compared to only 39 percent of men. Work, by contrast, was the dominant reason for men, especially for inter-state moves, where half of male migrants moved for employment against just 5 percent of female migrants. This pattern also shows up in academic research, which finds that males were consistently more likely to out-migrate specifically for jobs, while marriage remained the single biggest driver of migration overall.

Migration streams: villages, towns, and cities 🔗

Internal migration can also be classified by the type of area people leave and the type they arrive in: rural-to-rural, rural-to-urban, urban-to-rural, and urban-to-urban. Rural-to-rural movement is actually the single largest stream, accounting for roughly 54 percent of classifiable internal migration in 2011. But rural-to-urban migration has been climbing steadily, reaching about 48.5 percent of migration by stream in more recent estimates, largely because of expanding job opportunities in cities. Most of this movement also stays close to home: intra-state migration, within a person’s own state, made up almost 88 percent of all internal migration, while inter-state migration was a smaller but economically significant share.

International migration: crossing national borders 🔗

When a person crosses an international boundary to enter a country, they are classified as an immigrant to that country. When they leave their home country to settle elsewhere, they are classified as an emigrant from it. India’s story here is dominated overwhelmingly by emigration rather than immigration.

India’s global migration footprint 🔗

India is the world’s largest single origin country for international migrants, with an estimated 18.7 million Indian-born people living outside the country, according to World Bank migration estimates. This is a huge diaspora built up over decades of labour migration to the Gulf countries, professional migration to North America and Europe, and student migration for higher education. It stands in sharp contrast to the internal picture, where, as noted earlier, immigrants into India made up just a sliver of total recorded migration in the last full Census count.

The remittance economy 🔗

The financial return flow from this diaspora is enormous. India has been the world’s top remittance-receiving country every year since 2010, and in 2024 it received more than 137 billion dollars, the only country to ever cross the 100 billion dollar mark, according to the International Organization for Migration’s World Migration Report. South Asia as a region saw the highest remittance growth of any part of the world that year, driven largely by continued inflows to India, Pakistan, and Bangladesh. These transfers are not abstract macroeconomic numbers; they fund household consumption, education, and healthcare for families back home, and support India’s foreign exchange reserves at a national level.

Brain drain or brain gain? 🔗

When skilled workers, doctors, engineers, scientists, leave for opportunities abroad, origin countries risk what is commonly called brain drain, a loss of trained human capital that took years of public investment to build. The same IOM report notes that India has tried to convert this into brain gain through diaspora conventions and innovation hubs designed to draw scientists and entrepreneurs back, or at least keep them engaged remotely with India’s growth story. The Indian diaspora’s role in building out India’s technology sector is often cited as an example of this kind of two-way benefit, even though outcomes vary and not every skilled migrant eventually returns.

How migration reshapes population dynamics 🔗

Migration does more than move bodies from one place to another. It changes the underlying structure of the populations left behind and the populations received.

Sex ratio and age structure 🔗

Because men have historically migrated for work in much larger numbers than women, sending regions often see a shortage of working-age men, while receiving cities and industrial hubs see a temporary surplus of them. This sex-selective pattern in job-related migration, confirmed by Census-based research on migration streams, alters the effective sex ratio of the working-age population in both origin and destination areas, even when the overall national sex ratio stays the same. A mixed-methods study of labour migrant households in Tamil Nadu, published in a peer-reviewed international health journal, found that migration for work was heavily concentrated among adult males from historically marginalised and economically weaker households, which reshapes not just who is present in a village but also the composition of the families and elderly populations who remain behind, as documented by researchers studying internal migrant health outcomes.

Labour markets, cities, and left-behind regions 🔗

Receiving states and cities get an infusion of working-age labour that fuels construction, manufacturing, and services, but this also strains housing, water supply, and public services faster than local planning can keep pace. Government analysis of inter-state migration flows shows how a small set of destination states, particularly Maharashtra and Delhi, absorb a disproportionate share of the country’s mobile workforce, concentrating both economic opportunity and urban pressure in the same handful of places, as detailed in the Economic Advisory Council’s internal migration study. Sending states, meanwhile, often become more dependent on remittance income from both internal and international migrants, while also facing an ageing profile in the population that stays behind, since it is disproportionately the younger, working-age residents who leave first. Planning for schools, hospitals, and old-age services therefore has to account for a population that looks quite different on paper from the one that actually lives in a district day to day.

What do you think? If migrant-sending states like Uttar Pradesh and Bihar keep losing working-age residents to Maharashtra and Delhi, who should bear the cost of building services for the people left behind, the sending state, the receiving state, or the central government? And as India’s diaspora grows larger and remittances keep climbing, does that make migration a long-term development strategy for families, or a sign that local opportunities are still not good enough?

References

1. https://ipc2021.popconf.org/uploads/211137
2. https://prsindia.org/theprsblog/migration-in-india-and-the-impact-of-the-lockdown-on-migrants
3. https://eacpm.gov.in/wp-content/uploads/2024/12/FINAL-Internal-Migration-Project.docx-Publication-Version.pdf
4. https://www.migrationletters.com/index.php/ml/article/view/10538
5. https://www.business-standard.com/amp/economy/news/remittances-growth-to-india-may-halve-to-3-7-in-2024-says-world-bank-124062601220_1.html
6. https://www.business-standard.com/economy/news/india-tops-global-remittances-with-over-usd-137-billion-inflows-in-2024-un-126050501234_1.html
7. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5596496/