Infiltration Game: India’s demographic challenge

In his Independence Day speech, Prime Minister Narendra Modi warned of a “well-thought-out conspiracy” to alter India’s demography through illegal infiltration and announced a high-powered Demography Mission to counter it. That warning now feels particularly urgent when we look at our neighbourhood. Bangladesh’s recent civil unrest has reportedly already triggered fresh waves of infiltration. Now, Nepal is facing turmoil – and unlike Bangladesh, India shares an open border with Nepal, making the risk of mass inflows immediate and real. Across the Indian subcontinent, instability has become a norm, and each crisis in our neighbourhood risks becoming a demographic burden at home. This challenge deserves a deeper examination – not just politically, but through the lenses of evolutionary game theory and complex adaptive systems (CAS).

Imagine a population of small-bodied beetles. They live modestly, consuming food efficiently. Then a mutation introduces larger beetles – stronger at grabbing food, but hungrier due to higher metabolic needs. Which beetle type dominates in this population over time? The answer depends on average fitness. If the large beetles’ ability to secure food outweighs their metabolic disadvantage, they multiply. If not, the small beetles remain dominant. Eventually, one trait becomes evolutionarily stable: once widespread, no rival can displace it.

Illegal infiltration in human societies follows the same dynamics. Initially, the infiltrators are small in number. Their survival depends on whether the benefits of entry – access to resources, jobs, or political patronage – exceed the penalties imposed by the host society and outweigh the risks of detection and deportation. If benefits dominate, numbers grow. If costs prevail, their presence remains marginal.

Complex adaptive systems (CAS) as a framework provides a powerful perspective to understand how societies respond to demographic shifts, especially those driven by inorganic factors such as infiltration (inwards) or migration (outwards). Nation-states seen as CAS comprise diverse and interdependent agents (communities, institutions, and individuals) that self-organise to adapt to disruptions, developing new structures, processes, and routines to maintain stability. All systems are characterised by the need to maintain their status quo, but only up to a threshold.

Evolutionary game theory highlights tipping points. Populations may look stable for years, then suddenly flip once a threshold is crossed. Small-scale infiltration is often absorbed peacefully. But beyond a threshold, newcomers may create parallel institutions – schools, neighbourhoods, political blocs – that reinforce their presence. At that point, assimilation slows, host resistance hardens, and demographic change accelerates.

India’s history illustrates this. Bangladeshi migration into Assam and Bengal since the 1970s has been gradual but sustained enough to cross thresholds, producing political upheavals such as the Assam Movement and the recent National Register of Citizens (NRC) debates. Contrast this with the Tibetan refugee influx of the 1960s: small in number, State-supported, and culturally distinct, they assimilated without upheaval.

Unlike war, which provokes immediate retaliation, infiltration exploits time horizons. Each small flow seems tolerable, but collectively they create irreversible shifts – like compound interest, but in population terms.

CAS adapt through constant restructuring: rules, roles, and norms evolve in the “new normal”. Systems exhibit resilience, with the agents finding novel ways to cooperate, compete, or cohabitate, but within limits. When the stress exceeds societal adaptive capacity, turbulence follows.

Sri Lanka experienced a massive labour migration over the past few decades. With the exodus of youth seeking opportunities abroad draining the skilled workforce available within the country, institutions adapted by reshaping economic priorities. Even after the country experienced relatively stable economic growth, migration persisted, eventually straining health, education, and family structures, creating unemployment and social tensions that further fuelled unrest.

In Bangladesh, student protests that began over nepotism in civil service quotas (employment in the government with ultimate job security) rapidly evolved into a mass mobilisation against corruption, leading to political instability and regime change. What we are seeing in Nepal now mirrors what we have seen in Bangladesh – digitally-empowered youth swiftly organised and exposed the State’s vulnerabilities.

In each of these cases, adaptive mechanisms (including dialogue, minor reforms, and appeasement policies) proved insufficient, as the entire system alignment had shifted irreversibly.

Enforcement and incentives

What can be done? Here too, the beetle analogy offers clues. In evolutionary terms, enforcement lowers the payoff of being a large beetle. For societies, this means stronger border security, monitoring, and deportation mechanisms. Without credible enforcement, the advantage lies with infiltrators. Enforcement alone is costly and imperfect. A more lasting solution is to alter the payoffs. If informal networks and patronage make infiltration attractive, those networks must be dismantled. Conversely, if legitimate migration pathways are strengthened, legality becomes more attractive than illegality.

Unlike beetles, humans adapt. Migrants who assimilate, adopting the host society’s norms, languages, and institutions, reduce tensions and increase collective payoffs. If they cluster into exclusive blocs, the host population feels threatened, and resistance rises. Thus, integration policies matter as much as border control.

The concept of an “evolutionarily stable strategy” provides a useful test. A society is stable when small invasions cannot overturn the balance. Translated to demography, stability exists when institutions are strong enough either to prevent unauthorised inflows or to channel them into assimilation. Fragility, by contrast, arises when enforcement is weak, incentives reward infiltration, and assimilation breaks down. In such a setting, even modest inflows can accumulate into irreversible shifts.

PM Modi’s warning about demographic conspiracy can be read politically. But beneath the politics lies a simpler truth: if infiltration pays, it will grow; if it costs, it will shrink. Demography is a slow-moving variable, but also the most decisive. Once the equilibrium tilts, reversal is nearly impossible. Infiltration is not loud like war; it advances quietly, compounding its force over decades. India must shape its demographic destiny by design – before drift turns into fate.

(Rajeev is an assistant professor, and Srinivasan is a professor, at IIM Bangalore)