SmogRank / Episodes / Romania
South-eastern Europe, December 2025
For 2 days, from 10 to 11 December 2025, 17 cities in Romania, North Macedonia, Slovenia and 5 more countries had PM2.5 at least twice their usual for the time of year. The worst reading was Banja Luka, Srpska, Bosnia and Herzegovina: 171.0 µg/m³ on 10 December, about 3.2× its usual 53.7.
No cause named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 17 in 8 countries
Days 2 10 to 11 December 2025
Worst day 11 December 9 cities counted
Furthest above usual 5.8× Koper
Day by day
Play 11 December 9 cities at twice their usual or more
Szeged Pljevlja Bijelo Polje Sarajevo Calafat Nikšić Podgorica Skopje Gostivar Bar Dunaújváros Travnik Veles Debrecen Gyál Kochani Sofia Budapest Veszprém Cluj-Napoca Dej Sevlievo Zagreb Codlea Gabrovo Eisenzicken Maribor Ruse Popeşti-Leordeni Novo Mesto Celje Haskovo Graz Trbovlje Wolfsberg Ljubljana Kranj Klagenfurt am Wörthersee Varna Saalfelden am Steinernen Meer Tetovo Buftea Kumanovo Dimitrovgrad Craiova Târgu Mureş Ptuj Pécs Bucharest Iaşi Bihać Gorizia Belgrade Voluntari Ilinden Banja Luka Koper 7 Dec 8 9 10 11 12 13 14 Every measured city in the area, coloured by its PM2.5 that day; a dark ring marks a city at twice its usual or more. Bars: cities counted each day, coloured by their median level. Choose a day or press play; without JavaScript, the days link to that day's world ranking.
How it spread
Banja Luka Banja Luka, 7 December: 34.3 µg/m³, 0.6× usual Banja Luka, 8 December: 50.0 µg/m³, 0.9× usual Banja Luka, 9 December: 137.0 µg/m³, 2.6× usual Banja Luka, 10 December: 171.0 µg/m³, 3.2× usual Banja Luka, 11 December: no reading Banja Luka, 12 December: no reading Banja Luka, 13 December: no reading Banja Luka, 14 December: no reading Târgu Mureş Târgu Mureş, 7 December: 55.2 µg/m³, 1.5× usual Târgu Mureş, 8 December: 79.7 µg/m³, 2.1× usual Târgu Mureş, 9 December: 82.7 µg/m³, 2.2× usual Târgu Mureş, 10 December: 92.1 µg/m³, 2.5× usual Târgu Mureş, 11 December: 76.5 µg/m³, 2.1× usual Târgu Mureş, 12 December: 34.3 µg/m³, 0.9× usual Târgu Mureş, 13 December: 24.2 µg/m³, 0.7× usual Târgu Mureş, 14 December: 30.8 µg/m³, 0.8× usual Kumanovo Kumanovo, 7 December: 8.1 µg/m³, 0.3× usual Kumanovo, 8 December: 11.4 µg/m³, 0.4× usual Kumanovo, 9 December: 29.0 µg/m³, 0.9× usual Kumanovo, 10 December: 63.5 µg/m³, 2.0× usual Kumanovo, 11 December: 59.1 µg/m³, 1.9× usual Kumanovo, 12 December: 22.6 µg/m³, 0.7× usual Kumanovo, 13 December: 21.6 µg/m³, 0.7× usual Kumanovo, 14 December: 34.8 µg/m³, 1.1× usual Belgrade Belgrade, 7 December: 9.8 µg/m³, 0.4× usual Belgrade, 8 December: 35.1 µg/m³, 1.3× usual Belgrade, 9 December: 49.9 µg/m³, 1.8× usual Belgrade, 10 December: 61.4 µg/m³, 2.2× usual Belgrade, 11 December: 43.4 µg/m³, 1.6× usual Belgrade, 12 December: 23.1 µg/m³, 0.8× usual Belgrade, 13 December: 16.1 µg/m³, 0.6× usual Belgrade, 14 December: 22.4 µg/m³, 0.8× usual Koper Koper, 7 December: 4.4 µg/m³, 0.6× usual Koper, 8 December: 6.6 µg/m³, 0.9× usual Koper, 9 December: 10.5 µg/m³, 1.4× usual Koper, 10 December: 43.2 µg/m³, 5.8× usual Koper, 11 December: 33.4 µg/m³, 4.5× usual Koper, 12 December: 26.7 µg/m³, 3.6× usual Koper, 13 December: 4.6 µg/m³, 0.6× usual Koper, 14 December: 12.6 µg/m³, 1.7× usual Bihać Bihać, 7 December: 14.7 µg/m³, 0.9× usual Bihać, 8 December: 20.2 µg/m³, 1.3× usual Bihać, 9 December: 28.3 µg/m³, 1.8× usual Bihać, 10 December: 35.2 µg/m³, 2.2× usual Bihać, 11 December: 43.2 µg/m³, 2.7× usual Bihać, 12 December: 29.8 µg/m³, 1.9× usual Bihać, 13 December: 23.8 µg/m³, 1.5× usual Bihać, 14 December: 11.9 µg/m³, 0.7× usual Gorizia Gorizia, 7 December: 12.5 µg/m³, 0.8× usual Gorizia, 8 December: 13.2 µg/m³, 0.9× usual Gorizia, 9 December: 17.1 µg/m³, 1.1× usual Gorizia, 10 December: 33.4 µg/m³, 2.2× usual Gorizia, 11 December: 30.3 µg/m³, 2.0× usual Gorizia, 12 December: 13.5 µg/m³, 0.9× usual Gorizia, 13 December: 16.4 µg/m³, 1.1× usual Gorizia, 14 December: 14.8 µg/m³, 1.0× usual Ptuj Ptuj, 7 December: 24.9 µg/m³, 1.6× usual Ptuj, 8 December: 17.8 µg/m³, 1.1× usual Ptuj, 9 December: 26.8 µg/m³, 1.7× usual Ptuj, 10 December: 32.6 µg/m³, 2.1× usual Ptuj, 11 December: 38.1 µg/m³, 2.4× usual Ptuj, 12 December: no reading Ptuj, 13 December: 29.5 µg/m³, 1.9× usual Ptuj, 14 December: 18.1 µg/m³, 1.1× usual Pécs Pécs, 7 December: 11.0 µg/m³, 0.7× usual Pécs, 8 December: 19.0 µg/m³, 1.3× usual Pécs, 9 December: 26.9 µg/m³, 1.8× usual Pécs, 10 December: 30.6 µg/m³, 2.1× usual Pécs, 11 December: 20.6 µg/m³, 1.4× usual Pécs, 12 December: 16.8 µg/m³, 1.1× usual Pécs, 13 December: 6.6 µg/m³, 0.4× usual Pécs, 14 December: 4.1 µg/m³, 0.3× usual Tetovo Tetovo, 7 December: 32.9 µg/m³, 0.6× usual Tetovo, 8 December: 29.5 µg/m³, 0.5× usual Tetovo, 9 December: 37.3 µg/m³, 0.6× usual Tetovo, 10 December: 100.3 µg/m³, 1.7× usual Tetovo, 11 December: 115.5 µg/m³, 2.0× usual Tetovo, 12 December: 66.3 µg/m³, 1.2× usual Tetovo, 13 December: 40.4 µg/m³, 0.7× usual Tetovo, 14 December: 79.1 µg/m³, 1.4× usual Ilinden Ilinden, 7 December: 8.7 µg/m³, 0.2× usual Ilinden, 8 December: 9.4 µg/m³, 0.3× usual Ilinden, 9 December: 22.0 µg/m³, 0.6× usual Ilinden, 10 December: 42.5 µg/m³, 1.1× usual Ilinden, 11 December: 97.8 µg/m³, 2.6× usual Ilinden, 12 December: 37.3 µg/m³, 1.0× usual Ilinden, 13 December: 33.0 µg/m³, 0.9× usual Ilinden, 14 December: 46.1 µg/m³, 1.2× usual Voluntari Voluntari, 7 December: 12.4 µg/m³, 0.7× usual Voluntari, 8 December: 15.1 µg/m³, 0.8× usual Voluntari, 9 December: 16.4 µg/m³, 0.9× usual Voluntari, 10 December: 43.4 µg/m³, 2.3× usual Voluntari, 11 December: 45.5 µg/m³, 2.5× usual Voluntari, 12 December: 30.7 µg/m³, 1.7× usual Voluntari, 13 December: 38.2 µg/m³, 2.1× usual Voluntari, 14 December: 33.3 µg/m³, 1.8× usual Dimitrovgrad Dimitrovgrad, 7 December: 4.2 µg/m³, 0.2× usual Dimitrovgrad, 8 December: 6.0 µg/m³, 0.3× usual Dimitrovgrad, 9 December: 15.5 µg/m³, 0.8× usual Dimitrovgrad, 10 December: 21.8 µg/m³, 1.2× usual Dimitrovgrad, 11 December: 38.6 µg/m³, 2.1× usual Dimitrovgrad, 12 December: 37.0 µg/m³, 2.0× usual Dimitrovgrad, 13 December: 23.0 µg/m³, 1.3× usual Dimitrovgrad, 14 December: 31.2 µg/m³, 1.7× usual Buftea Buftea, 7 December: 11.2 µg/m³, 0.6× usual Buftea, 8 December: 13.5 µg/m³, 0.7× usual Buftea, 9 December: 16.5 µg/m³, 0.9× usual Buftea, 10 December: 31.6 µg/m³, 1.7× usual Buftea, 11 December: 37.4 µg/m³, 2.0× usual Buftea, 12 December: 27.4 µg/m³, 1.5× usual Buftea, 13 December: 29.2 µg/m³, 1.6× usual Buftea, 14 December: 26.4 µg/m³, 1.4× usual Iaşi Iaşi, 7 December: 14.3 µg/m³, 0.9× usual Iaşi, 8 December: 14.9 µg/m³, 1.0× usual Iaşi, 9 December: 13.6 µg/m³, 0.9× usual Iaşi, 10 December: 26.6 µg/m³, 1.7× usual Iaşi, 11 December: 33.0 µg/m³, 2.2× usual Iaşi, 12 December: 15.3 µg/m³, 1.0× usual Iaşi, 13 December: 14.6 µg/m³, 1.0× usual Iaşi, 14 December: 14.9 µg/m³, 1.0× usual Craiova Craiova, 7 December: 8.8 µg/m³, 0.6× usual Craiova, 8 December: 10.9 µg/m³, 0.8× usual Craiova, 9 December: 13.8 µg/m³, 1.0× usual Craiova, 10 December: 23.2 µg/m³, 1.6× usual Craiova, 11 December: 30.0 µg/m³, 2.1× usual Craiova, 12 December: 24.9 µg/m³, 1.8× usual Craiova, 13 December: 19.8 µg/m³, 1.4× usual Craiova, 14 December: 13.7 µg/m³, 1.0× usual Bucharest Bucharest, 7 December: 10.6 µg/m³, 0.8× usual Bucharest, 8 December: 11.0 µg/m³, 0.8× usual Bucharest, 9 December: 14.5 µg/m³, 1.1× usual Bucharest, 10 December: 25.7 µg/m³, 1.9× usual Bucharest, 11 December: 29.7 µg/m³, 2.2× usual Bucharest, 12 December: 21.0 µg/m³, 1.6× usual Bucharest, 13 December: 25.1 µg/m³, 1.9× usual Bucharest, 14 December: 22.0 µg/m³, 1.6× usual 7 Dec 8 9 10 11 12 13 14 Every counted city, in the order the episode reached them, 3 days before to 3 after. Each square is a day, coloured by that day's PM2.5; outlined: at twice the city's usual or more. Good 0–50
Moderate 51–100
Sensitive groups 101–150
Unhealthy 151–200
Very unhealthy 201–300
Hazardous 301+
Every city it reached
City Days Highest Usual Above usual
Koper Urban Municipality of Koper, Slovenia 1 10 December 7.5 5.8× Banja Luka Srpska, Bosnia and Herzegovina 1 10 December 53.7 3.2× Bihać Federation of B&H, Bosnia and Herzegovina 1 11 December 16.0 2.7× Ilinden Ilinden, North Macedonia 1 11 December 37.0 2.6× Târgu Mureş Mureș County, Romania 1 10 December 37.2 2.5× Voluntari Ilfov, Romania 1 11 December 18.5 2.5× Ptuj Urban Municipality of Ptuj, Slovenia 1 11 December 15.8 2.4× Gorizia Friuli Venezia Giulia, Italy 1 10 December 14.9 2.2× Belgrade Central Serbia, Serbia 1 10 December 27.5 2.2× Bucharest Bucharest, Romania 1 11 December 13.5 2.2× Iaşi Iași County, Romania 1 11 December 15.3 2.2× Craiova Dolj, Romania 1 11 December 14.1 2.1× Dimitrovgrad Haskovo, Bulgaria 1 11 December 18.4 2.1× Pécs Baranya, Hungary 1 10 December 14.7 2.1× Kumanovo Kumanovo, North Macedonia 1 10 December 31.0 2.0× Buftea Ilfov, Romania 1 11 December 18.5 2.0× Tetovo Tetovo, North Macedonia 1 11 December 57.5 2.0×
Daily means in µg/m³. Usual: the city's median for this time of year (its days within 21 days of the date, every year, leaving out the week around it). Above usual: its highest day against that.
Against other episodes in Romania and North Macedonia
Number 2 of 4 episodes in Romania and North Macedonia since our records began, by cities reached.
Bars: cities reached; colour: the level of the episode's highest daily reading.
Use this page SmogRank, South-eastern Europe, December 2025: 17 cities with PM2.5 at twice their usual or more, 10 to 11 December 2025, smogrank.com/episodes/2025-12-south-eastern-europe (accessed 2 October 2026).
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You're welcome to reuse a single chart, image or figure with this citation and a link. Terms .
An episode is a run of days when many cities close to each other (four or more within 350 km on a day, 8 or more in all) each had a daily PM2.5 mean of at least 25 µg/m³ and at least 2 times their usual for that time of year. Found in our own measurements, not picked by hand. How we find episodes . Values are each city's daily mean of its own monitors; causes are the usual kinds for a pattern like this, not a confirmed source.
