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. 301ZgierzŁódź Voivodeship, Poland 15%42 of 286
  2. 302DębicaSubcarpathia, Poland 14%41 of 285
  3. 303Lat KrabangBangkok, Thailand 14%37 of 258
  4. 304KumanovoKumanovo, North Macedonia 14%40 of 279
  5. 305SukhothaiSukhothai, Thailand 14%35 of 245
  6. 306YerevanYerevan, Armenia 14%40 of 285
  7. 307TlaquepaqueJalisco, Mexico 14%36 of 257
  8. 308Jastrzębie ZdrójSilesia, Poland 14%40 of 286
  9. 309Si Maha PhotPrachin Buri, Thailand 14%33 of 237
  10. 310KimjeJeollabuk-do, South Korea 14%35 of 252
  11. 311HavířovMoravian-Silesian Region, Czechia 14%39 of 284
  12. 312PrayagrajUttar Pradesh, India 14%35 of 255
  13. 313KavadarciKavadarci, North Macedonia 13%35 of 260
  14. 314PubalGyeonggi-do, South Korea 13%33 of 247
  15. 315Gostivarlast full day 10 OctGostivar, North Macedonia 13%32 of 241
  16. 316AnseongGyeonggi-do, South Korea 13%32 of 241
  17. 317PuducherryPuducherry, India 13%31 of 234
  18. 318Hacienda Santa FeJalisco, Mexico 13%34 of 257
  19. 319Bang NaBangkok, Thailand 13%34 of 258
  20. 320Nong KhaemBangkok, Thailand 13%34 of 258
  21. 321Udon ThaniUdon Thani, Thailand 13%33 of 253
  22. 322Milanlast full day 11 OctLombardy, Italy 13%36 of 280
  23. 323Nong Bua LamphuNong Bua Lamphu, Thailand 13%33 of 257
  24. 324Nakhon RatchasimaNakhon Ratchasima, Thailand 13%32 of 250
  25. 325TulareCalifornia, United States 13%34 of 268
  26. 326AsanChungcheongnam-do, South Korea 13%35 of 277
  27. 327KoprivnicaKoprivnica-Križevci, Croatia 12%31 of 249
  28. 328San Luis Potosílast full day 1 OctSan Luis Potosí, Mexico 12%26 of 210
  29. 329PyeongtaekGyeonggi-do, South Korea 12%35 of 283
  30. 330JhānsiUttar Pradesh, India 12%29 of 236
  31. 331QuillotaValparaiso, Chile 12%34 of 279
  32. 332ToméBiobio, Chile 12%31 of 255
  33. 333SirohiRajasthan, India 12%30 of 247
  34. 334San Pedro de la PazBiobio, Chile 12%34 of 280
  35. 335Sannazzaro de' BurgondiLombardy, Italy 12%33 of 273
  36. 336AguascalientesAguascalientes, Mexico 12%34 of 282
  37. 337ConcepciónBiobio, Chile 12%29 of 241
  38. 338VelesVeles, North Macedonia 12%25 of 209
  39. 339BitolaBitola, North Macedonia 12%34 of 286
  40. 340Wodzisław ŚląskiSilesia, Poland 12%33 of 278
  41. 341Gevgelijalast full day 10 OctGevgelija, North Macedonia 12%28 of 236
  42. 342Nakło nad NoteciąKujawsko-Pomorskie, Poland 12%32 of 272
  43. 343SerilingampalleTelangana, India 12%30 of 255
  44. 344Nakhon PathomNakhon Pathom, Thailand 12%29 of 247
  45. 345Bueng KumBangkok, Thailand 12%30 of 258
  46. 346RzeszówSubcarpathia, Poland 12%33 of 286
  47. 347KrakówLesser Poland, Poland 12%33 of 286
  48. 348Saphan SungBangkok, Thailand 12%28 of 243
  49. 349BuanJeollabuk-do, South Korea 11%31 of 270
  50. 350BhilaiChhattisgarh, India 11%28 of 244
  51. 351Hwaseong-siGyeonggi-do, South Korea 11%31 of 272
  52. 352BārmerRajasthan, India 11%28 of 246
  53. 353SejongSejong-si, South Korea 11%30 of 264
  54. 354Bang Bo DistrictSamut Prakan, Thailand 11%25 of 221
  55. 355Bang PakongChachoengsao, Thailand 11%28 of 249
  56. 356Baia MareMaramureş, Romania 11%24 of 214
  57. 357AranyaprathetSa Kaeo, Thailand 11%25 of 224
  58. 358SurinSurin, Thailand 11%27 of 242
  59. 359Sighetu Marmaţieilast full day 10 OctMaramureş, Romania 11%31 of 279
  60. 360Ban Talat BuengChon Buri, Thailand 11%27 of 243
  61. 361TurinPiedmont, Italy 11%29 of 262
  62. 362RevúcaBanská Bystrica Region, Slovakia 11%31 of 281
  63. 363ČaňaKošice Region, Slovakia 11%30 of 276
  64. 364KarvináMoravian-Silesian Region, Czechia 11%31 of 286
  65. 365OstravaMoravian-Silesian Region, Czechia 11%31 of 286
  66. 366PoznańGreater Poland, Poland 11%31 of 286
  67. 367IksanJeollabuk-do, South Korea 11%30 of 280
  68. 368Strumicalast full day 10 OctStrumica, North Macedonia 11%25 of 234
  69. 369YesanChungcheongnam-do, South Korea 11%30 of 283
  70. 370ŻaryLubusz, Poland 11%30 of 284
  71. 371TarnówLesser Poland, Poland 11%30 of 285
  72. 372ChiguayanteBiobio, Chile 10%29 of 277
  73. 373Peschiera del GardaVeneto, Italy 10%29 of 277
  74. 374ŠahyNitra Region, Slovakia 10%29 of 281
  75. 375PodgoricaPodgorica, Montenegro 10%26 of 252
  76. 376HwadoGyeonggi-do, South Korea 10%27 of 263
  77. 377TangjinChungcheongnam-do, South Korea 10%27 of 264
  78. 378CieszynSilesia, Poland 10%28 of 274
  79. 379GunsanJeollabuk-do, South Korea 10%29 of 284
  80. 380SuwonGyeonggi-do, South Korea 10%29 of 284
  81. 381IncheonIncheon, South Korea 10%29 of 285
  82. 382Bucheon-siGyeonggi-do, South Korea 10%29 of 285
  83. 383HaarlemNorth Holland, The Netherlands 10%29 of 285
  84. 384WanjuJeollabuk-do, South Korea 10%28 of 276
  85. 385Lak SiBangkok, Thailand 10%26 of 258
  86. 386Bang KapiBangkok, Thailand 10%26 of 258
  87. 387SeoulSeoul, South Korea 10%28 of 282
  88. 388LegionowoMazovia, Poland 10%28 of 283
  89. 389QuinteroValparaiso, Chile 10%28 of 284
  90. 390OsanGyeonggi-do, South Korea 10%28 of 284
  91. 391ToruńKujawsko-Pomorskie, Poland 10%28 of 284
  92. 392MariglianoCampania, Italy 10%26 of 264
  93. 393WrocławLower Silesia, Poland 10%28 of 286
  94. 394Frýdek-MístekMoravian-Silesian Region, Czechia 10%28 of 286
  95. 395SkopjeGrad Skopje, North Macedonia 10%28 of 286
  96. 396Ban Samae DamBangkok, Thailand 10%25 of 258
  97. 397Sai MaiBangkok, Thailand 10%25 of 258
  98. 398Valašské MeziříčíZlín, Czechia 10%26 of 269
  99. 399GwangmyeongGyeonggi-do, South Korea 10%27 of 281
  100. 400HongseongChungcheongnam-do, South Korea 10%26 of 271

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).