SmogRank / History / May 1, 2023

Most polluted cities on May 1, 2023

1,489 cities ranked by their average PM2.5 over the day; the worst was Bloemfontein, South Africa, at 96.0 µg/m³. Each city's own local calendar day.

Bad-air episodes during May 1, 2023. All episodes.

← Bloemfontein 96.0 µg/m³ 90 µg/m³15 WHO 24-hour guideline
Every city ranked for May 1, 2023, one column each, worst on the left and cleanest on the right; height is PM2.5 in µg/m³. Point at it to read a city; tap to open it.
  1. 1BloemfonteinFree State, South Africa
    1796.4×
  2. 2Puerto VarasLos Lagos Region, Chile
    1715.6×
  3. 3BamakoBamako, Mali
    1574.3×
  4. 4BrawleyCalifornia, United States
    1574.3×
  5. 5OsornoLos Lagos Region, Chile
    1564.2×
  6. 6Kathmandulow-cost sensorsBagmati Province, Nepal
    1493.7×
  7. 7La UniónLos Ríos Region, Chile
    1423.5×
  8. 8GreizThuringia, Germany
    1403.4×
  9. 8ValdiviaLos Ríos Region, Chile
    1403.4×
  10. 10CholulaPuebla, Mexico
    1393.4×
  11. 11BeijingBeijing, China
    1363.3×
  12. 12Peshawarlow-cost sensorsKhyber Pakhtunkhwa, Pakistan
    1353.3×
  13. 13Dhakalow-cost sensorsDhaka Division, Bangladesh
    1343.3×
  14. 14HanoiHanoi, Vietnam
    1333.2×
  15. 15DěčínÚstí nad Labem Region, Czechia
    1293.1×
  16. 16Ga-RankuwaNorth West, South Africa
    1233.0×
  17. 17DelhiDelhi, India
    1222.9×
  18. 18NacimientoBiobio, Chile
    1222.9×
  19. 19HualpénBiobio, Chile
    1222.9×
  20. 20CoronelBiobio, Chile
    1152.7×
  21. 21Suphan BuriSuphan Buri, Thailand
    1112.6×
  22. 22Addis AbabaAddis Ababa, Ethiopia
    1102.6×
  23. 23GuangzhouGuangdong, China
    1092.6×
  24. 24NanNan, Thailand
    1092.6×
  25. 25CranbrookBritish Columbia, Canada
    1082.6×
  26. 26Puerto MonttLos Lagos Region, Chile
    1082.5×
  27. 26CelayaGuanajuato, Mexico
    1082.5×
  28. 28Lahorelow-cost sensorsPunjab, Pakistan
    1072.5×
  29. 29HualquiBiobio, Chile
    1052.5×
  30. 30San Mateo AtencoMéxico, Mexico
    1042.5×
  31. 31AltenburgThuringia, Germany
    1042.4×
  32. 32XonacatlánMéxico, Mexico
    1022.4×
  33. 33Sing BuriSing Buri, Thailand
    1022.4×
  34. 34TolucaMéxico, Mexico
    1012.4×
  35. 35CuranilahueBiobio, Chile
    1012.4×
  36. 36TemucoAraucania, Chile
    992.3×
  37. 36MexicaliBaja California, Mexico
    992.3×
  38. 38RabinalBaja Verapaz, Guatemala
    992.3×
  39. 38Guatemala CityGuatemala, Guatemala
    992.3×
  40. 40Chiang RaiChiang Rai, Thailand
    982.3×
  41. 40TalaganteSantiago Metropolitan, Chile
    982.3×
  42. 42Chiang MaiChiang Mai, Thailand
    972.3×
  43. 43Bang NaBangkok, Thailand
    972.2×
  44. 44Silao de la VictoriaGuanajuato, Mexico
    972.2×
  45. 45Mladá BoleslavCentral Bohemia, Czechia
    962.2×
  46. 46Puerto AysénAysén, Chile
    952.2×
  47. 46AguascalientesAguascalientes, Mexico
    952.2×
  48. 48ShanghaiShanghai, China
    942.1×
  49. 49LampangLampang, Thailand
    942.1×
  50. 49SantiagoSantiago Metropolitan, Chile
    942.1×
  51. 49Khlong Sam WaBangkok, Thailand
    942.1×
  52. 52BerounCentral Bohemia, Czechia
    922.1×
  53. 53PristinaPristina, Kosovo
    922.1×
  54. 54LamphunLamphun, Thailand
    912.0×
  55. 54Bueng KumBangkok, Thailand
    912.0×
  56. 56Tha BoNong Khai, Thailand
    912.0×
  57. 57BrightonEngland, United Kingdom
    902.0×
  58. 58Bang Khun ThianBangkok, Thailand
    892.0×
  59. 59Nong KhaemBangkok, Thailand
    892.0×
  60. 60KladnoCentral Bohemia, Czechia
    881.9×
  61. 61PhayaoPhayao, Thailand
    881.9×
  62. 61YangonYangon, Myanmar
    881.9×
  63. 61Si Maha PhotPrachin Buri, Thailand
    881.9×
  64. 64Khan Na YaoBangkok, Thailand
    881.9×
  65. 65Mae SaiChiang Rai, Thailand
    881.9×
  66. 66Islamabadlow-cost sensorsIslamabad, Pakistan
    881.9×
  67. 66TalcahuanoBiobio, Chile
    881.9×
  68. 68Ubon RatchathaniUbon Ratchathani, Thailand
    871.9×
  69. 69Saphan SungBangkok, Thailand
    871.9×
  70. 70BelmopanCayo District, Belize
    871.9×
  71. 70San CarlosÑuble, Chile
    871.9×
  72. 72Chai NatChai Nat, Thailand
    861.9×
  73. 72SalamancaGuanajuato, Mexico
    861.9×
  74. 74LiberecLiberec Region, Czechia
    861.9×
  75. 75VereenigingGauteng, South Africa
    851.8×
  76. 75ThembisaGauteng, South Africa
    851.8×
  77. 77Ban Samae DamBangkok, Thailand
    851.8×
  78. 77Lagoslow-cost sensorsLagos, Nigeria
    851.8×
  79. 79Lat KrabangBangkok, Thailand
    851.8×
  80. 80LoeiLoei, Thailand
    851.8×
  81. 81ShenyangLiaoning, China
    851.8×
  82. 82PraguePrague, Czechia
    841.8×
  83. 83PhraePhrae, Thailand
    841.8×
  84. 83San Francisco TlalcilalcalpanMéxico, Mexico
    841.8×
  85. 85AntananarivoAnalamanga, Madagascar
    841.8×
  86. 86Nong ChokBangkok, Thailand
    831.8×
  87. 87Kinshasalow-cost sensorsKinshasa, Democratic Republic of the Congo
    831.8×
  88. 88Ciudad NezahualcoyotlMéxico, Mexico
    831.8×
  89. 89UttaraditUttaradit, Thailand
    831.7×
  90. 90Udon ThaniUdon Thani, Thailand
    821.7×
  91. 91Ban ChangRayong, Thailand
    821.7×
  92. 91ChillánÑuble, Chile
    821.7×
  93. 93AshgabatAshgabat, Turkmenistan
    821.7×
  94. 93Kamphaeng PhetKamphaeng Phet, Thailand
    821.7×
  95. 93CuernavacaMorelos, Mexico
    821.7×
  96. 96Nakhon SawanNakhon Sawan, Thailand
    811.7×
  97. 96ConcepciónBiobio, Chile
    811.7×
  98. 98Ciudad JuárezChihuahua, Mexico
    811.7×
  99. 99BangkokBangkok, Thailand
    811.7×
  100. 100BéthuneHauts-de-France, France
    801.7×
  101. 100BrnoSouth Moravian, Czechia
    801.7×
  102. 100EtwatwaGauteng, South Africa
    801.7×
  103. 103Khlong LuangPathum Thani, Thailand
    801.7×
  104. 104KigaliKigali, Rwanda
    801.6×
  105. 104Bang KapiBangkok, Thailand
    801.6×
  106. 104ValenciennesHauts-de-France, France
    801.6×
  107. 104León de los AldamaGuanajuato, Mexico
    801.6×
  108. 108Ban Khlong PrawetBangkok, Thailand
    801.6×
  109. 109Lak SiBangkok, Thailand
    801.6×
  110. 110La SerenaCoquimbo Region, Chile
    791.6×
  111. 111IrapuatoGuanajuato, Mexico
    791.6×
  112. 112Hradec KrálovéHradec Králové Region, Czechia
    791.6×
  113. 112QuinteroValparaiso, Chile
    791.6×
  114. 114LilleHauts-de-France, France
    791.6×
  115. 115CopiapóAtacama, Chile
    781.6×
  116. 116ĆuprijaCentral Serbia, Serbia
    781.6×
  117. 116PhetchabunPhetchabun, Thailand
    781.6×
  118. 116MenenFlanders, Belgium
    781.6×
  119. 119Ciudad Benito JuárezNuevo León, Mexico
    781.6×
  120. 120Sai MaiBangkok, Thailand
    781.6×
  121. 121RatchaburiRatchaburi, Thailand
    781.6×
  122. 121Bang Bo DistrictSamut Prakan, Thailand
    781.6×
  123. 123RengoO'Higgins Region, Chile
    771.6×
  124. 124AcharnésAttica, Greece
    771.5×
  125. 124RayongRayong, Thailand
    771.5×
  126. 124Canvey IslandEngland, United Kingdom
    771.5×
  127. 127SasolburgFree State, South Africa
    771.5×
  128. 127KadaňÚstí nad Labem Region, Czechia
    771.5×
  129. 127Los ÁngelesBiobio, Chile
    771.5×
  130. 130Mae SotTak, Thailand
    771.5×
  131. 130CoquimboCoquimbo Region, Chile
    771.5×
  132. 132ChanthaburiChanthaburi, Thailand
    771.5×
  133. 132CauquenesMaule Region, Chile
    771.5×
  134. 134AthensAttica, Greece
    761.5×
  135. 135ChiguayanteBiobio, Chile
    761.5×
  136. 136RancaguaO'Higgins Region, Chile
    751.5×
  137. 136GuanajuatoGuanajuato, Mexico
    751.5×
  138. 138TocopillaAntofagasta, Chile
    751.5×
  139. 138Puente AltoSantiago Metropolitan, Chile
    751.5×
  140. 140HavířovMoravian-Silesian Region, Czechia
    751.5×
  141. 141Mueang NonthaburiNonthaburi, Thailand
    751.5×
  142. 141AranyaprathetSa Kaeo, Thailand
    751.5×
  143. 141Mexico CityMexico City, Mexico
    751.5×
  144. 144AntofagastaAntofagasta, Chile
    751.5×
  145. 145TakTak, Thailand
    741.4×
  146. 145Laem ChabangChon Buri, Thailand
    741.4×
  147. 145TlaxcalaTlaxcala, Mexico
    741.4×
  148. 145CoyhaiqueAysén, Chile
    741.4×
  149. 149IzegemFlanders, Belgium
    741.4×
  150. 150Lop BuriLopburi, Thailand
    741.4×
  151. 150AbasoloGuanajuato, Mexico
    741.4×
  152. 152PakxanBolikhamsai, Laos
    741.4×
  153. 152PortsmouthEngland, United Kingdom
    741.4×
  154. 152San Pedro de la PazBiobio, Chile
    741.4×
  155. 155KlerksdorpNorth West, South Africa
    741.4×
  156. 156Ústí nad LabemÚstí nad Labem Region, Czechia
    741.4×
  157. 157LinaresMaule Region, Chile
    731.4×
  158. 158San Andrés TuxtlaVeracruz, Mexico
    731.4×
  159. 159TokozaGauteng, South Africa
    731.4×
  160. 159Ban Talat BuengChon Buri, Thailand
    731.4×
  161. 159MonsWallonia, Belgium
    731.4×
  162. 162MostÚstí nad Labem Region, Czechia
    731.4×
  163. 163ObrenovacCentral Serbia, Serbia
    721.4×
  164. 163TournaiWallonia, Belgium
    721.4×
  165. 165Si Sa KetSi Sa Ket, Thailand
    721.4×
  166. 165SaraburiSaraburi, Thailand
    721.4×
  167. 165PueblaPuebla, Mexico
    721.4×
  168. 168SukhothaiSukhothai, Thailand
    721.4×
  169. 168Phra Nakhon Si AyutthayaPhra Nakhon Si Ayutthaya, Thailand
    721.4×
  170. 168RoeselareFlanders, Belgium
    721.4×
  171. 171San Miguel de AllendeGuanajuato, Mexico
    721.4×
  172. 172KalasinKalasin, Thailand
    711.3×
  173. 172DouaiHauts-de-France, France
    711.3×
  174. 174JohannesburgGauteng, South Africa
    711.3×
  175. 174Phra PradaengSamut Prakan, Thailand
    711.3×
  176. 174KortrijkFlanders, Belgium
    711.3×
  177. 177CanterburyEngland, United Kingdom
    711.3×
  178. 177Santiago de QuerétaroQuerétaro, Mexico
    711.3×
  179. 179Samut SakhonSamut Sakhon, Thailand
    701.3×
  180. 179YumaArizona, United States
    701.3×
  181. 181KhalándrionAttica, Greece
    701.3×
  182. 181BelgradeCentral Serbia, Serbia
    701.3×
  183. 183KhartoumKhartoum, Sudan
    701.3×
  184. 183YalaYala, Thailand
    701.3×
  185. 185Wan ChaiWan Chai, Hong Kong
    701.3×
  186. 186KanchanaburiKanchanaburi, Thailand
    701.3×
  187. 186Jastrzębie ZdrójSilesia, Poland
    701.3×
  188. 188Samut PrakanSamut Prakan, Thailand
    691.3×
  189. 188Nakhon PathomNakhon Pathom, Thailand
    691.3×
  190. 188CuricóMaule Region, Chile
    691.3×
  191. 191KoksijdeFlanders, Belgium
    691.3×
  192. 191Czechowice-DziedziceSilesia, Poland
    691.3×
  193. 193Naucalpan de JuárezMéxico, Mexico
    691.3×
  194. 193GaryIndiana, United States
    691.3×
  195. 195PirotCentral Serbia, Serbia
    691.2×
  196. 195Novi PazarCentral Serbia, Serbia
    691.2×
  197. 195PhichitPhichit, Thailand
    691.2×
  198. 195PurmerendNorth Holland, The Netherlands
    691.2×
  199. 199LazarevacCentral Serbia, Serbia
    691.2×
  200. 199Khon KaenKhon Kaen, Thailand
    691.2×

Top 200 of 1,489 shown.

Good0–50
Moderate51–100
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

Use this board

SmogRank, most polluted cities, PM2.5, May 1, 2023, smogrank.com/history/2023-05-01 (accessed 2 Oct 2026).

Download top 10 (PNG)

You're welcome to reuse a single chart, image or figure with this citation and a link. Terms.