SmogRank / Rankings

All 3,198 cities by unhealthy days, this year

Every city with enough measurements in this window, worst first.

CPCB in India: no readings since 12 Oct (488 monitors). EEA in Spain: no readings since 13 Oct (310 monitors). Their cities show older figures or are missing from this board, not clean.

Ranked by unhealthy days: the share of each city's measured days with a daily mean over 35.4 µg/m³ (US AQI 101+), Unhealthy for Sensitive Groups or worse on the US EPA's scale. Cities with the same share are ordered by more unhealthy days, then by the higher average.

  1. 401Phra PradaengSamut Prakan, Thailand 10%24 of 251
  2. 402Ansan-siGyeonggi-do, South Korea 10%27 of 284
  3. 403Sakon NakhonSakon Nakhon, Thailand 9%24 of 253
  4. 404YeongjuGyeongsangbuk-do, South Korea 9%26 of 277
  5. 405KinzanChungcheongnam-do, South Korea 9%21 of 226
  6. 406AlessandriaPiedmont, Italy 9%19 of 205
  7. 407Viña del MarValparaiso, Chile 9%26 of 281
  8. 408KazincbarcikaBorsod-Abaúj-Zemplén, Hungary 9%26 of 281
  9. 409SilcharAssam, India 9%23 of 251
  10. 410Nong ChokBangkok, Thailand 9%23 of 252
  11. 411OpoleOpole Voivodeship, Poland 9%25 of 274
  12. 412CiechanówMazovia, Poland 9%25 of 274
  13. 413Gimpo-siGyeonggi-do, South Korea 9%26 of 285
  14. 414SingaporeSingapore 9%26 of 286
  15. 415NiskoSubcarpathia, Poland 9%25 of 275
  16. 416TratTrat, Thailand 9%23 of 254
  17. 417YeojuGyeonggi-do, South Korea 9%25 of 277
  18. 418OkcheonNorth Chungcheong, South Korea 9%23 of 256
  19. 419Zacatepec de HidalgoMorelos, Mexico 9%25 of 279
  20. 420MunsanGyeonggi-do, South Korea 9%25 of 279
  21. 421NamsaJeollabuk-do, South Korea 9%23 of 258
  22. 422South Lake TahoeCalifornia, United States 9%20 of 225
  23. 423Miskolclast full day 21 SeptBorsod-Abaúj-Zemplén, Hungary 9%22 of 248
  24. 424KutinaSisak-Moslavina, Croatia 9%24 of 272
  25. 425LotaBiobio, Chile 9%20 of 227
  26. 426ZamośćLublin, Poland 9%25 of 284
  27. 427Gapyeonglast full day 30 SeptGyeonggi-do, South Korea 9%19 of 216
  28. 428JeongeupJeollabuk-do, South Korea 9%24 of 273
  29. 429Ban ChangRayong, Thailand 9%20 of 228
  30. 430Icheon-siGyeonggi-do, South Korea 9%24 of 274
  31. 431BydgoszczKujawsko-Pomorskie, Poland 9%25 of 286
  32. 432YŏnmuChungcheongnam-do, South Korea 9%24 of 278
  33. 433KikindaVojvodina, Serbia 9%24 of 279
  34. 434CheonanChungcheongnam-do, South Korea 9%24 of 282
  35. 435PuchuncavíValparaiso, Chile 8%23 of 271
  36. 436Goyang-siGyeonggi-do, South Korea 8%24 of 283
  37. 437Guri-siGyeonggi-do, South Korea 8%24 of 285
  38. 438RacibórzSilesia, Poland 8%24 of 285
  39. 439TijuanaBaja California, Mexico 8%22 of 262
  40. 440StarachowiceŚwiętokrzyskie, Poland 8%24 of 286
  41. 441ShakaskraalKwaZulu-Natal, South Africa 8%24 of 286
  42. 442NilópolisRio de Janeiro, Brazil 8%23 of 275
  43. 443ComoLombardy, Italy 8%20 of 240
  44. 444SangjuGyeongsangbuk-do, South Korea 8%22 of 265
  45. 445Phra Nakhon Si AyutthayaPhra Nakhon Si Ayutthaya, Thailand 8%20 of 241
  46. 446ConcónValparaiso, Chile 8%23 of 278
  47. 447CrescentinoPiedmont, Italy 8%21 of 254
  48. 448ChungjuNorth Chungcheong, South Korea 8%23 of 279
  49. 449TetovoTetovo, North Macedonia 8%18 of 220
  50. 450Craiovalast full day 10 OctDolj, Romania 8%23 of 282
  51. 451MielecSubcarpathia, Poland 8%23 of 282
  52. 452Chinch'ŏnNorth Chungcheong, South Korea 8%22 of 270
  53. 453BrzegOpole Voivodeship, Poland 8%23 of 284
  54. 454Anyang-siGyeonggi-do, South Korea 8%23 of 285
  55. 455Seongnam-siGyeonggi-do, South Korea 8%23 of 285
  56. 456Yongsan-dongSeoul, South Korea 8%22 of 275
  57. 457Yangp'yŏngGyeonggi-do, South Korea 8%21 of 263
  58. 458Ganghwa-gunIncheon, South Korea 8%22 of 276
  59. 459KoesanNorth Chungcheong, South Korea 8%22 of 276
  60. 460Nyíregyházalast full day 21 SeptSzabolcs-Szatmár-Bereg, Hungary 8%20 of 252
  61. 461GwangjuGyeonggi-do, South Korea 8%22 of 278
  62. 462NikšićOpština Nikšić, Montenegro 8%21 of 267
  63. 463KrompachyKošice Region, Slovakia 8%21 of 268
  64. 464WŏnjuGangwon-do, South Korea 8%22 of 281
  65. 465AcerraCampania, Italy 8%21 of 269
  66. 466OlomoucOlomouc Region, Czechia 8%22 of 282
  67. 467PruszkówMazovia, Poland 8%21 of 270
  68. 468MantuaLombardy, Italy 8%21 of 270
  69. 469TřinecMoravian-Silesian Region, Czechia 8%22 of 286
  70. 470PrinevilleOregon, United States 8%22 of 286
  71. 471Cheongju-siNorth Chungcheong, South Korea 8%21 of 279
  72. 472JarosławSubcarpathia, Poland 8%21 of 279
  73. 473NamyangjuGyeonggi-do, South Korea 8%21 of 280
  74. 474Kędzierzyn-KoźleOpole Voivodeship, Poland 7%21 of 281
  75. 475MadrasOregon, United States 7%21 of 282
  76. 476TocopillaAntofagasta, Chile 7%20 of 269
  77. 477CheorwonGangwon-do, South Korea 7%21 of 283
  78. 478VinovoPiedmont, Italy 7%20 of 270
  79. 479WabuGyeonggi-do, South Korea 7%18 of 243
  80. 480BangkokBangkok, Thailand 7%19 of 258
  81. 481Codlealast full day 10 OctBrașov County, Romania 7%17 of 231
  82. 482HarareHarare, Zimbabwe 7%18 of 245
  83. 483WschowaLubusz, Poland 7%21 of 286
  84. 484SintansinDaejeon, South Korea 7%18 of 251
  85. 485PrešovPrešov Region, Slovakia 7%20 of 281
  86. 486SaraburiSaraburi, Thailand 7%17 of 239
  87. 487ŻyrardówMazovia, Poland 7%18 of 254
  88. 488RadomMazovia, Poland 7%20 of 283
  89. 489BoryeongChungcheongnam-do, South Korea 7%19 of 269
  90. 490NangenJeollabuk-do, South Korea 7%17 of 242
  91. 491HanamGyeonggi-do, South Korea 7%20 of 285
  92. 492Jelenia GóraLower Silesia, Poland 7%20 of 286
  93. 493Wan ChaiWan Chai, Hong Kong 7%15 of 217
  94. 494PrzemyślSubcarpathia, Poland 7%19 of 275
  95. 495Augustówlast full day 5 OctPodlasie, Poland 7%16 of 233
  96. 496GimcheonGyeongsangbuk-do, South Korea 7%19 of 279
  97. 497Konstancin-JeziornaMazovia, Poland 7%19 of 279
  98. 498NampaIdaho, United States 7%19 of 280
  99. 499YeonilGyeongsangbuk-do, South Korea 7%18 of 266
  100. 500GumiGyeongsangbuk-do, South Korea 7%19 of 281

What stands behind each figure: Checked at 2+ sites One reference monitor Low-cost sensors About these marks

Low-cost sensors: consumer units, counted only in cities with no government-grade monitor; they read close to reference monitors on the whole, but 15 to 25% high in humid air. How we use them.

Good0–50
Moderate51–100
Unhealthy for sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

The US EPA's Air Quality Index for PM2.5 (2024 breakpoints). Show values as: µg/m³ · US AQI · India AQI · China AQI · European AQI · UK DAQI · Canada AQHI+. About the scales

Not covered: the government monitoring networks of China, Turkey and Iran, which publish only on their own websites. We are building the reader for China's network. The networks of Turkey and Iran don't answer requests from outside their countries, so we can't read them. Most cities there are missing from this board, not clean. Why.

Use this board

SmogRank, all cities ranked by unhealthy days (PM2.5), this year to 14 Oct 2026, 07:00 UTC: each city's share of its measured days with a daily mean over 35.4 µg/m³, cities measured on 70% or more of the days since 1 January (at least 14). Monitor data from national networks via OpenAQ and the publishers listed at smogrank.com/sources. smogrank.com/rankings?w=year&by=days. Ranked on low-cost sensors, with no reference monitor in the city: #4 Kampala and #8 Faisalabad. Some values from Sensor.Community, ODbL. Some readings from Department of Environment, Nepal; Vietnam's government monitors; Aurassure; RMCAB (Secretaría Distrital de Ambiente, Bogotá); Umhverfisstofnun (Environment Agency of Iceland), no reuse terms published.

Download top 10 by average (PNG)

You're welcome to reuse a single chart, image or figure with this citation and a link. Terms. Raw monitor readings in bulk are published by OpenAQ, under each provider's licence.

Updated 2026-10-14 07:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index. Some low-cost readings: Sensor.Community, ODbL (data and licence). Some readings: Department of Environment, Nepal; Vietnam's government monitors; Aurassure; RMCAB (Secretaría Distrital de Ambiente, Bogotá); Umhverfisstofnun (Environment Agency of Iceland), no reuse terms published (why we use them).