What is unfolding in the occupied territories of Ukraine – in Mariupol above all, but also across swathes of Donetsk, Luhansk, Zaporizhzhia and Kherson oblasts – is the deliberate erasure of a Ukrainian population and its substitution with a Russian one.

There is historical precedent for the behaviour of the Russian authorities. After the Second World War, Soviet authorities prevented the largely Estonian population of Narva from returning to their city following wartime evacuation, and systematically resettled Russian workers there instead. A city that was 65 per cent ethnic Estonian in 1934 became around 97 per cent Russian-speaking by the late Soviet period, a demographic transformation that outlasted the USSR and continues to shape Estonian security calculations today. What Russia is doing in Mariupol, in occupied Ukraine, follows the same logic: the deliberate remaking of a city’s population as an instrument of political control, conducted with the confidence that the world will eventually accommodate the result.

Before the full-scale invasion, Mariupol was home to approximately 450,000 people, a majority-Ukrainian city that had undergone a significant cultural and civic revival following 2014. The siege of 2022, conducted over a brutal 86 days, devastated the city. Human Rights Watch documented at least 8,034 excess deaths in the first year alone, a figure the organisation considers a significant undercount; Ukrainian official estimates reached 22,000 by mid-2022. Hundreds of thousands fled. The mayor’s office recorded that at least 33,000 residents were deported to Russia or separatist-controlled territory by April 2022; Petro Andriushchenko, then adviser to the exiled mayor, documented a further 27,000 held simultaneously in Russian filtration camps in Donetsk Oblast, where they were subjected to biometric registration, interrogation, document confiscation and, in many cases, deportation to distant regions of Russia. By May 2023, around 120,000 pre-war residents remained in the city. The figure today stands at approximately 100,000.

The demographic structure of that residual population is itself revealing. Of the 100,000 who remain, around 70,000, or 70 per cent, are pensioners aged over 60. Working-age adults number just 13,000. Children aged 17 and under account for only 17,000. This is not a population in recovery. The age pyramid is inverted, and the situation is unlikely to improve.

According to figures provided by the Centre for the Study of Occupation, based in Dnipro, among those who were living in Mariupol before the invasion and remain under occupation, approximately 600 people die each month. Against this backdrop, roughly 90 births occur, a rate itself declining at around ten per cent every two years, yielding a net loss to natural causes alone of some 510 people per month. The contrast with government-controlled Ukrainian territory is stark: even accounting for violent deaths, the death-to-birth ratio there in 2025 was approximately 3:1. Birth rates are among the most reliable indicators of a population’s confidence in its own future. The people of Mariupol who lived through the siege and remain are not having children.

At the same time, working-age adults from among the pre-war population are leaving at roughly 200 per month. Mariupol under occupation is a surveillance state in miniature: movement is monitored, the Ukrainian language has been suppressed, civic institutions have been dissolved, and those with known connections to the Ukrainian military or civil society face the risk of detention. There is no compensatory inflow. It is a place most Ukrainians leave when they can.

At a combined rate of approximately 710 pre-war residents lost per month, through death, departure, and the collapse of birth rates, their number will fall below 5,000 within 12 years, even setting aside the compounding effects of population ageing and violent death. Within half a generation, Russia will have effectively erased the population of a city of 450,000.

The other side of this process is the importation of a replacement population. According to data provided by the Centre for the Study of Occupation on settler inflows, the number of Russian citizens in Mariupol increased by at least 80,000 between 2023 and 2025, at a current rate of approximately 2,200 per month. On these projections, Russians will numerically outnumber those who called Mariupol home before the invasion by the end of this year; within three years, by more than two to one; within a decade, the replacement will be near-total.

This migration is not spontaneous. Russia has constructed a federal infrastructure for demographic resettlement. The ‘Zemsky’ programmes, covering teachers, doctors, cultural workers and sports coaches, offer working-age Russian citizens financial packages, housing assistance and preferential mortgages at two per cent interest to relocate to what the Kremlin describes as its ‘new regions’. In 2026 alone, 1.18 billion roubles were allocated for teacher relocation, and the cultural workers programme received 2.5 billion. Meanwhile, the doctors programme was provided with six billion roubles in 2024. These are federal budget lines administered through occupation ministries.

The settlers arriving under these schemes are overwhelmingly working-age adults moving with families: such as a teacher from Tatarstan who relocated to occupied Donetsk with her husband and four children; a couple from Khabarovsk, who both took school positions in occupied Luhansk, bringing their four children; a choreographer from Siberia, who purchased an apartment in Luhansk with her relocation payment; a sound engineer from Irkutsk, who describes occupied Sievierodonetsk as professionally enriching. Each represents not merely one additional Russian resident, but a family unit that will raise its children as Russian citizens on Ukrainian soil.

None of this is improvised. In August 2023, the Institute for the Study of War (ISW) assessed that Ukrainian partisans had obtained a Russian occupation planning document setting out a ten-year programme for Mariupol: explicit repopulation targets, the systematic removal of ethnic Ukrainians, and preferential incentives for Russian settlers. ISW concluded that Russia’s conduct ‘likely amounts to a deliberate ethnic cleansing campaign in addition to being apparent violations of the Convention on the Prevention and Punishment of the Crime of Genocide’. The plan is on schedule.

Mariupol is an advanced case, not an anomaly. Recent monitoring confirms equivalent patterns of population decline among pre-war residents and organised Russian resettlement across all four occupied oblasts. In Kherson, administrators imported from across Russia have assumed control at almost every level of governance; several are now subject to international sanctions for their roles in deporting Ukrainian children and dismantling Ukrainian education. The approach follows a recognisable Soviet template: mass importation of settlers to dilute, displace and ultimately supersede a pre-existing population, underwritten by the conviction that the land and its development belong by civilisational right to Russia.

The de-Ukrainianisation of Mariupol is not a by-product of military necessity. The deportation and filtration of civilians, the suppression of Ukrainian language and identity, the federal funding of settler migration, the ten-year demographic plan: these constitute, in aggregate, a systematic and state-directed campaign to displace a population from its territory and replace it with another. ISW has applied the term ethnic cleansing without equivocation. The Genocide Convention and the Rome Statute both provide further frameworks; whether courts ultimately reach a determination under those instruments is a matter for legal proceedings and political will. What is not in serious analytical dispute is the character of what is occurring.

Any settlement, as unlikely as it may seem right now, would not stop the inflow of Russian settlers; it would encourage it, as stabilised conditions lower the risks involved with relocation. If the past provides any guide, it suggests that demographic transformation does not pause when the guns fall silent. Rather, facts on the ground can be presented as a fait accompli that any subsequent political settlement will be obliged to accommodate. What Russia is acquiring, above all, is time.

The question of what a Russified Mariupol ultimately becomes is worth asking. History offers one answer: a demographically transformed city, frozen in place, its origins gradually obscured and its new reality treated as simply the way things are. But there are darker possibilities. It could become a military launchpad, much like the one that Russia made of Crimea after 2014, using the peninsula to stage the very invasion that destroyed Mariupol itself. It could, in the event of Ukrainian military reconquest, become a spoiler region within a reunited Ukraine, a concentration of settlers with Russian citizenship and pro-Russian political loyalties engineered to destabilise any future settlement from within. Or it could simply be absorbed into Russia and forgotten, the violence and the ethnic cleansing buried for good. One thing is clear: Russia will not return Mariupol at the negotiating table willingly.

None of these futures is palatable. All of them were chosen, both by Russia’s actions and by everyone else’s inaction.