SmogRank / History / July 31, 2023

Most polluted cities on July 31, 2023

1,891 cities ranked by their average PM2.5 over the day; the worst was Piedras Negras, Mexico, at 986.0 µg/m³. Each city's own local calendar day.

← Piedras Negras 986.0 µg/m³ 900 µg/m³15 WHO 24-hour guideline
Every city ranked for July 31, 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. 1Piedras NegrasCoahuila, Mexico
    500+65.7×
  2. 2CoyhaiqueAysén, Chile
    1927.6×
  3. 3NacimientoBiobio, Chile
    1776.2×
  4. 4IndioCalifornia, United States
    1705.5×
  5. 5KamloopsBritish Columbia, Canada
    1695.4×
  6. 6Puerto VarasLos Lagos Region, Chile
    1644.9×
  7. 7MexicaliBaja California, Mexico
    1604.6×
  8. 8RancaguaO'Higgins Region, Chile
    1604.6×
  9. 9CuricóMaule Region, Chile
    1604.5×
  10. 10SantiagoSantiago Metropolitan, Chile
    1574.3×
  11. 11RengoO'Higgins Region, Chile
    1564.2×
  12. 11OsornoLos Lagos Region, Chile
    1564.2×
  13. 13Los ÁngelesBiobio, Chile
    1554.1×
  14. 14LinaresMaule Region, Chile
    1533.9×
  15. 15BanningCalifornia, United States
    1523.8×
  16. 16CuranilahueBiobio, Chile
    1503.7×
  17. 17CoronelBiobio, Chile
    1493.7×
  18. 18San CarlosÑuble, Chile
    1443.5×
  19. 19Puerto AysénAysén, Chile
    1443.5×
  20. 20ChillánÑuble, Chile
    1433.5×
  21. 21Puente AltoSantiago Metropolitan, Chile
    1373.3×
  22. 22TalaganteSantiago Metropolitan, Chile
    1353.3×
  23. 23Dhakalow-cost sensorsDhaka Division, Bangladesh
    1313.2×
  24. 24TemucoAraucania, Chile
    1243.0×
  25. 25JakartaJakarta, Indonesia
    1243.0×
  26. 26ValdiviaLos Ríos Region, Chile
    1182.8×
  27. 27ToméBiobio, Chile
    1162.8×
  28. 28Peshawarlow-cost sensorsKhyber Pakhtunkhwa, Pakistan
    1152.7×
  29. 29CalexicoCalifornia, United States
    1122.7×
  30. 30QuillotaValparaiso, Chile
    1092.6×
  31. 31Lahorelow-cost sensorsPunjab, Pakistan
    1072.5×
  32. 32HualquiBiobio, Chile
    1062.5×
  33. 33TalcahuanoBiobio, Chile
    1042.5×
  34. 34CauquenesMaule Region, Chile
    1042.4×
  35. 35TalcaMaule Region, Chile
    1022.4×
  36. 36LotaBiobio, Chile
    1012.4×
  37. 37Puerto MonttLos Lagos Region, Chile
    992.3×
  38. 38AntananarivoAnalamanga, Madagascar
    992.3×
  39. 39Viña del MarValparaiso, Chile
    982.3×
  40. 40La UniónLos Ríos Region, Chile
    972.3×
  41. 41DelhiDelhi, India
    962.2×
  42. 42ConcepciónBiobio, Chile
    952.2×
  43. 43Santa Anita - Los FicusLima region, Peru
    952.2×
  44. 44CoquimboCoquimbo Region, Chile
    952.2×
  45. 45ChiguayanteBiobio, Chile
    912.0×
  46. 46DushanbeDushanbe, Tajikistan
    902.0×
  47. 47HanoiHanoi, Vietnam
    881.9×
  48. 48KolkataWest Bengal, India
    861.9×
  49. 49ConcónValparaiso, Chile
    851.8×
  50. 50QuinteroValparaiso, Chile
    851.8×
  51. 51AntofagastaAntofagasta, Chile
    831.8×
  52. 52PristinaPristina, Kosovo
    821.7×
  53. 53TlaquepaqueJalisco, Mexico
    821.7×
  54. 53Ciudad JuárezChihuahua, Mexico
    821.7×
  55. 55FontanaCalifornia, United States
    821.7×
  56. 56Islamabadlow-cost sensorsIslamabad, Pakistan
    811.7×
  57. 56Thunder BayOntario, Canada
    811.7×
  58. 58VictorvilleCalifornia, United States
    811.7×
  59. 59MostaIl-Mosta, Malta
    791.6×
  60. 60RiversideCalifornia, United States
    781.6×
  61. 61Las VegasNevada, United States
    771.6×
  62. 62Şabāḩ as SālimMubārak al Kabīr, Kuwait
    771.5×
  63. 63SofiaSofia-Capital, Bulgaria
    771.5×
  64. 63LimaLima Province, Peru
    771.5×
  65. 65GuangzhouGuangdong, China
    771.5×
  66. 66Jurupa ValleyCalifornia, United States
    761.5×
  67. 66Boulder CityNevada, United States
    761.5×
  68. 68Karachilow-cost sensorsSindh, Pakistan
    761.5×
  69. 68CopiapóAtacama, Chile
    761.5×
  70. 70HendersonNevada, United States
    741.4×
  71. 71TocopillaAntofagasta, Chile
    741.4×
  72. 72XonacatlánMéxico, Mexico
    741.4×
  73. 72La SerenaCoquimbo Region, Chile
    741.4×
  74. 72AricaArica y Parinacota Region, Chile
    741.4×
  75. 75Great FallsMontana, United States
    731.4×
  76. 76NagaiYamagata, Japan
    731.4×
  77. 77SalorTashkent Region, Uzbekistan
    721.4×
  78. 78ShenyangLiaoning, China
    721.4×
  79. 78BrawleyCalifornia, United States
    721.4×
  80. 80ChennaiTamil Nadu, India
    721.4×
  81. 81LublinLublin, Poland
    711.3×
  82. 82La Línea de la ConcepciónAndalusia, Spain
    711.3×
  83. 83Lake ElsinoreCalifornia, United States
    711.3×
  84. 84GlendoraCalifornia, United States
    711.3×
  85. 85Alto HospicioTarapacá, Chile
    701.3×
  86. 86SarajevoFederation of B&H, Bosnia and Herzegovina
    701.3×
  87. 87Los AngelesCalifornia, United States
    691.3×
  88. 88YalaYala, Thailand
    691.2×
  89. 89AdaOklahoma, United States
    691.2×
  90. 90CalamaAntofagasta, Chile
    681.2×
  91. 91San Francisco TlalcilalcalpanMéxico, Mexico
    681.2×
  92. 92Hat YaiSongkhla, Thailand
    681.2×
  93. 93Spring ValleyNevada, United States
    671.2×
  94. 94El CentroCalifornia, United States
    671.2×
  95. 95Victoria de DurangoDurango, Mexico
    671.2×
  96. 96São PauloSão Paulo, Brazil
    671.2×
  97. 97TolucaMéxico, Mexico
    661.2×
  98. 98BakuBaki, Azerbaijan
    661.2×
  99. 98SatunSatun, Thailand
    661.2×
  100. 98Villa Poeta José Gálvez BarrenecheaLima region, Peru
    661.2×
  101. 98DallasTexas, United States
    661.2×
  102. 102KanchanaburiKanchanaburi, Thailand
    661.1×
  103. 102IshinomakiMiyagi, Japan
    661.1×
  104. 104EnterpriseNevada, United States
    661.1×
  105. 105FillmoreCalifornia, United States
    651.1×
  106. 106RatchaburiRatchaburi, Thailand
    651.1×
  107. 106MooreOklahoma, United States
    651.1×
  108. 108Ban ChangRayong, Thailand
    651.1×
  109. 108SagaeYamagata, Japan
    651.1×
  110. 110TakasakiGunma, Japan
    651.1×
  111. 110Simi ValleyCalifornia, United States
    651.1×
  112. 110Khlong Sam WaBangkok, Thailand
    651.1×
  113. 113Tagajō-shiMiyagi, Japan
    651.1×
  114. 113San RoqueAndalusia, Spain
    651.1×
  115. 115Ciudad ApodacaNuevo León, Mexico
    641.1×
  116. 115Oklahoma CityOklahoma, United States
    641.1×
  117. 115DetroitMichigan, United States
    641.1×
  118. 115Summerlin SouthNevada, United States
    641.1×
  119. 119SuperiorWisconsin, United States
    641.1×
  120. 119Saphan SungBangkok, Thailand
    641.1×
  121. 121YoshiokaMiyagi, Japan
    641.1×
  122. 121SendaiMiyagi, Japan
    641.1×
  123. 121Natori-shiMiyagi, Japan
    641.1×
  124. 121IwanumaMiyagi, Japan
    641.1×
  125. 121Baton RougeLouisiana, United States
    641.1×
  126. 126Kathmandulow-cost sensorsBagmati Province, Nepal
    641.1×
  127. 127Bang NaBangkok, Thailand
    631.1×
  128. 127SakataYamagata, Japan
    631.1×
  129. 127DuluthMinnesota, United States
    631.1×
  130. 130Bang Bo DistrictSamut Prakan, Thailand
    631.0×
  131. 130EdmontonAlberta, Canada
    631.0×
  132. 132AlgecirasAndalusia, Spain
    631.0×
  133. 132SliemaTas-Sliema, Malta
    631.0×
  134. 134AsprópyrgosAttica, Greece
    631.0×
  135. 134Ban Samae DamBangkok, Thailand
    631.0×
  136. 134BurbankCalifornia, United States
    631.0×
  137. 137IyoEhime, Japan
    631.0×
  138. 138Fort WorthTexas, United States
    631.0×
  139. 138Fort St. JohnBritish Columbia, Canada
    631.0×
  140. 140ShinjōYamagata, Japan
    621.0×
  141. 140MatsushimaMiyagi, Japan
    621.0×
  142. 140HigashineYamagata, Japan
    621.0×
  143. 140New OrleansLouisiana, United States
    621.0×
  144. 140MinneapolisMinnesota, United States
    621.0×
  145. 140Minami-SōmaFukushima, Japan
    621.0×
  146. 146YonezawaYamagata, Japan
    621.0×
  147. 146BamakoBamako, Mali
    621.0×
  148. 148McAlesterOklahoma, United States
    621.0×
  149. 148ŌsakiMiyagi, Japan
    621.0×
  150. 148San Salvador TizatlalliMéxico, Mexico
    621.0×
  151. 151JeddahMecca Region, Saudi Arabia
    621.0×
  152. 151ColomboWestern Province, Sri Lanka
    621.0×
  153. 151Nong KhaemBangkok, Thailand
    621.0×
  154. 151HuelvaAndalusia, Spain
    621.0×
  155. 151EdmondOklahoma, United States
    621.0×
  156. 156MukdahanMukdahan, Thailand
    621.0×
  157. 156ShibataNiigata, Japan
    621.0×
  158. 158Hua HinPrachuap Khiri Khan, Thailand
    611.0×
  159. 158GroßostheimBavaria, Germany
    611.0×
  160. 158Ponca CityOklahoma, United States
    611.0×
  161. 158DearbornMichigan, United States
    611.0×
  162. 162Santa BarbaraCalifornia, United States
    611.0×
  163. 162San Francisco De BorjaLima region, Peru
    611.0×
  164. 164BeijingBeijing, China
    611.0×
  165. 164Niitsu-honchōNiigata, Japan
    611.0×
  166. 164KiryūGunma, Japan
    611.0×
  167. 167TsuruokaYamagata, Japan
    611.0×
  168. 167KesennumaMiyagi, Japan
    611.0×
  169. 167TaylorMichigan, United States
    611.0×
  170. 167ComptonCalifornia, United States
    611.0×
  171. 167Santa ClaritaCalifornia, United States
    611.0×
  172. 167Thousand OaksCalifornia, United States
    611.0×
  173. 173SadaoSongkhla, Thailand
    610.9×
  174. 173Khan Na YaoBangkok, Thailand
    610.9×
  175. 175Sing BuriSing Buri, Thailand
    600.9×
  176. 176NaganoNagano, Japan
    600.9×
  177. 176ShreveportLouisiana, United States
    600.9×
  178. 178Phra PradaengSamut Prakan, Thailand
    600.9×
  179. 178YamagataYamagata, Japan
    600.9×
  180. 178ShonaiYamagata, Japan
    600.9×
  181. 181AlgiersAlgiers, Algeria
    600.9×
  182. 181DentonTexas, United States
    600.9×
  183. 183CuencaCastille-La Mancha, Spain
    590.9×
  184. 184PhetchabunPhetchabun, Thailand
    590.9×
  185. 184NiigataNiigata, Japan
    590.9×
  186. 184KushiroHokkaido, Japan
    590.9×
  187. 184Redwood CityCalifornia, United States
    590.9×
  188. 184Sai MaiBangkok, Thailand
    590.9×
  189. 189Phra Nakhon Si AyutthayaPhra Nakhon Si Ayutthaya, Thailand
    590.9×
  190. 190Wan ChaiWan Chai, Hong Kong
    590.9×
  191. 190ShironeNiigata, Japan
    590.9×
  192. 190Ulu BedokSingapore
    590.9×
  193. 190HelenaMontana, United States
    590.9×
  194. 190HigashimatsushimaMiyagi, Japan
    590.9×
  195. 195HyderabadTelangana, India
    590.9×
  196. 195SevillaAndalusia, Spain
    590.9×
  197. 195JōetsuNiigata, Japan
    590.9×
  198. 198ShibukawaGunma, Japan
    580.9×
  199. 198ChitoseHokkaido, Japan
    580.9×
  200. 198West MemphisArkansas, United States
    580.9×

Top 200 of 1,891 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

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SmogRank, most polluted cities, PM2.5, July 31, 2023, smogrank.com/history/2023-07-31 (accessed 2 Oct 2026).

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