SmogRank / Rankings

All 3,290 cities by unhealthy days, last 30 days

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. =495PortoPorto, Portugal 0%0 of 30
  2. =495ŻywiecSilesia, Poland 0%0 of 30
  3. =495AsunciónAsuncion, Paraguay 0%0 of 29
  4. =495Yongsan-dongSeoul, South Korea 0%0 of 29
  5. =505NiskoSubcarpathia, Poland 0%0 of 30
  6. =505KrielMpumalanga, South Africa 0%0 of 23
  7. =505Samut PrakanSamut Prakan, Thailand 0%0 of 30
  8. =505NeiliTaiwan, Taiwan 0%0 of 30
  9. =505SeoulSeoul, South Korea 0%0 of 30
  10. =505Cheongju-siNorth Chungcheong, South Korea 0%0 of 29
  11. =505ThièsThies, Senegal 0%0 of 30
  12. =505KatowiceSilesia, Poland 0%0 of 30
  13. =505FresnoCalifornia, United States 0%0 of 30
  14. =514JouniehMount Lebanon, Lebanon 0%0 of 30
  15. =514MiaoliTaiwan, Taiwan 0%0 of 30
  16. =514SuwonGyeonggi-do, South Korea 0%0 of 30
  17. =514Anyang-siGyeonggi-do, South Korea 0%0 of 30
  18. =514GyálPest County, Hungary 0%0 of 30
  19. =514LitvínovÚstí nad Labem Region, Czechia 0%0 of 27
  20. =514SinanJeollanam-do, South Korea 0%0 of 29
  21. =521RadomMazovia, Poland 0%0 of 30
  22. =521ShenzhenTaiwan, Taiwan 0%0 of 30
  23. =523RzeszówSubcarpathia, Poland 0%0 of 30
  24. =523KumanovoKumanovo, North Macedonia 0%0 of 30
  25. =523PrayagrajUttar Pradesh, India 0%0 of 26
  26. =523BuziTaiwan, Taiwan 0%0 of 30
  27. =523Tsuen WanTsuen Wan, Hong Kong 0%0 of 26
  28. =523AsanChungcheongnam-do, South Korea 0%0 of 29
  29. =523HaenamJeollanam-do, South Korea 0%0 of 30
  30. =523CheonanChungcheongnam-do, South Korea 0%0 of 30
  31. =523Chinch'ŏnNorth Chungcheong, South Korea 0%0 of 30
  32. =523Donghae CityGangwon-do, South Korea 0%0 of 29
  33. =523HuelvaAndalusia, Spain 0%0 of 28
  34. =523ŁódźŁódź Voivodeship, Poland 0%0 of 30
  35. =523Mexico CityMexico City, Mexico 0%0 of 30
  36. =523Atotonilco de TulaHidalgo, Mexico 0%0 of 30
  37. =523TaoyuanTaiwan, Taiwan 0%0 of 30
  38. =538MiddelburgMpumalanga, South Africa 0%0 of 30
  39. =538Hartbeespoortlast full day 8 OctNorth West, South Africa 0%0 of 25
  40. =538WaegwanGyeongsangbuk-do, South Korea 0%0 of 29
  41. =538NonsanChungcheongnam-do, South Korea 0%0 of 29
  42. =538MunsanGyeonggi-do, South Korea 0%0 of 29
  43. =543Dejlast full day 10 OctCluj County, Romania 0%0 of 21
  44. =543ČaňaKošice Region, Slovakia 0%0 of 28
  45. =543Chiang MaiChiang Mai, Thailand 0%0 of 30
  46. =543SaraburiSaraburi, Thailand 0%0 of 30
  47. =543MiamiOklahoma, United States 0%0 of 29
  48. =548SangjuGyeongsangbuk-do, South Korea 0%0 of 29
  49. =548Imperial BeachCalifornia, United States 0%0 of 30
  50. =548Sai MaiBangkok, Thailand 0%0 of 30
  51. =551Jilavalast full day 10 OctIlfov, Romania 0%0 of 27
  52. =551Roi EtRoi Et, Thailand 0%0 of 30
  53. =551Amnat CharoenAmnat Charoen, Thailand 0%0 of 30
  54. =551TaipeiTaiwan, Taiwan 0%0 of 30
  55. =551SuncheonJeollanam-do, South Korea 0%0 of 29
  56. =551JeonjuJeollabuk-do, South Korea 0%0 of 29
  57. =551AbidjanAbidjan Autonomous District, Ivory Coast 0%0 of 22
  58. =551Czechowice-DziedziceSilesia, Poland 0%0 of 30
  59. =551Ciudad ApodacaNuevo León, Mexico 0%0 of 26
  60. =560Popeşti-Leordenilast full day 10 OctIlfov, Romania 0%0 of 27
  61. =560KalasinKalasin, Thailand 0%0 of 30
  62. =560Bucheon-siGyeonggi-do, South Korea 0%0 of 30
  63. =560NangenJeollabuk-do, South Korea 0%0 of 25
  64. =560Saronnolast full day 11 OctLombardy, Italy 0%0 of 25
  65. =565BitolaBitola, North Macedonia 0%0 of 30
  66. =565CenturionGauteng, South Africa 0%0 of 27
  67. =565TrangTrang, Thailand 0%0 of 30
  68. =565Udon ThaniUdon Thani, Thailand 0%0 of 30
  69. =565PhatthalungPhatthalung, Thailand 0%0 of 30
  70. =565ShulinTaipei, Taiwan 0%0 of 30
  71. =565Hwaseong-siGyeonggi-do, South Korea 0%0 of 30
  72. =565Bielsko-BialaSilesia, Poland 0%0 of 30
  73. =565BresciaLombardy, Italy 0%0 of 29
  74. =565RiversideCalifornia, United States 0%0 of 30
  75. =575LublinLublin, Poland 0%0 of 30
  76. =575KielceŚwiętokrzyskie, Poland 0%0 of 30
  77. =575JarosławSubcarpathia, Poland 0%0 of 30
  78. =575Mueang NonthaburiNonthaburi, Thailand 0%0 of 30
  79. =575VictoriaCentral and Western, Hong Kong 0%0 of 30
  80. =575ZgierzŁódź Voivodeship, Poland 0%0 of 30
  81. =575SejongSejong-si, South Korea 0%0 of 30
  82. =582Calafatlast full day 10 OctDolj, Romania 0%0 of 22
  83. =582ZhudongTaiwan, Taiwan 0%0 of 30
  84. =582Koch'angJeollabuk-do, South Korea 0%0 of 27
  85. =582BailénAndalusia, Spain 0%0 of 27
  86. =582OmegnaPiedmont, Italy 0%0 of 22
  87. =587Buftealast full day 10 OctIlfov, Romania 0%0 of 27
  88. =587TongyeongGyeongsangnam-do, South Korea 0%0 of 29
  89. =587PřerovOlomouc Region, Czechia 0%0 of 30
  90. =587CieszynSilesia, Poland 0%0 of 30
  91. =587AcerraCampania, Italy 0%0 of 29
  92. =587SarajevoFederation of B&H, Bosnia and Herzegovina 0%0 of 30
  93. =587New Taipei CityTaipei, Taiwan 0%0 of 30
  94. =594Nong ChokBangkok, Thailand 0%0 of 30
  95. =594Lop BuriLopburi, Thailand 0%0 of 29
  96. =594HsinchuTaiwan, Taiwan 0%0 of 30
  97. =594OlomoucOlomouc Region, Czechia 0%0 of 30
  98. =594São José do Rio PretoSão Paulo, Brazil 0%0 of 30
  99. =599PołaniecŚwiętokrzyskie, Poland 0%0 of 30
  100. =599Kamphaeng PhetKamphaeng Phet, Thailand 0%0 of 30

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), last 30 days 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 21 or more of the 30 days. Monitor data from national networks via OpenAQ and the publishers listed at smogrank.com/sources. smogrank.com/rankings?w=30d&by=days. Ranked on low-cost sensors, with no reference monitor in the city: #1 Peshawar, #2 Multan, #5 Kasur, #7 Gujranwala, #8 Lahore, #9 Faisalabad and #10 Jammu. Some values from Sensor.Community, ODbL. Some readings from Vietnam's government monitors; Department of Environment, Nepal; Aurassure; RMCAB (Secretaría Distrital de Ambiente, Bogotá); Love My Air (City and County of Denver); 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: Vietnam's government monitors; Department of Environment, Nepal; Aurassure; RMCAB (Secretaría Distrital de Ambiente, Bogotá); Love My Air (City and County of Denver); Umhverfisstofnun (Environment Agency of Iceland), no reuse terms published (why we use them).