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.

=599Chai NatChai Nat, Thailand 0%0 of 29
=599Uijeongbu-siGyeonggi-do, South Korea 0%0 of 30
=599GwangjuGwangju, South Korea 0%0 of 30
=599ChungjuNorth Chungcheong, South Korea 0%0 of 30
=599DěčínÚstí nad Labem Region, Czechia 0%0 of 30
=599PoznańGreater Poland, Poland 0%0 of 30
=607LamphunLamphun, Thailand 0%0 of 30
=607Uthai ThaniUthai Thani, Thailand 0%0 of 30
=607Maha SarakhamMaha Sarakham, Thailand 0%0 of 28
=607Sha TinSha Tin, Hong Kong 0%0 of 29
=607Laem ChabangChon Buri, Thailand 0%0 of 29
=607PraguePrague, Czechia 0%0 of 30
=607BerounCentral Bohemia, Czechia 0%0 of 30
=607ToruńKujawsko-Pomorskie, Poland 0%0 of 30
=607BydgoszczKujawsko-Pomorskie, Poland 0%0 of 30
=607SolofraCampania, Italy 0%0 of 29
=607AostaAosta Valley, Italy 0%0 of 30
=607Parque Industrial Ciudad Mitraslast full day 8 OctNuevo León, Mexico 0%0 of 23
=619LegionowoMazovia, Poland 0%0 of 30
=619WŏnjuGangwon-do, South Korea 0%0 of 30
=619SeosanChungcheongnam-do, South Korea 0%0 of 29
=619MiryangGyeongsangnam-do, South Korea 0%0 of 24
=619SinhyeonGyeongsangnam-do, South Korea 0%0 of 29
=619HanamGyeonggi-do, South Korea 0%0 of 30
=619OstravaMoravian-Silesian Region, Czechia 0%0 of 30
=619KrakówLesser Poland, Poland 0%0 of 30
=619BrzegOpole Voivodeship, Poland 0%0 of 30
=619ShreveportLouisiana, United States 0%0 of 29
=629Iaşilast full day 10 OctIași County, Romania 0%0 of 27
=629MielecSubcarpathia, Poland 0%0 of 30
=629KavadarciKavadarci, North Macedonia 0%0 of 30
=629ThiruvananthapuramKerala, India 0%0 of 25
=629UttaraditUttaradit, Thailand 0%0 of 29
=629Mahlowlast full day 10 OctBrandenburg, Germany 0%0 of 25
=629Sainte-Geneviève-des-BoisÎle-de-France, France 0%0 of 30
=629BorgomaneroPiedmont, Italy 0%0 of 30
=637Bragadirulast full day 10 OctIlfov, Romania 0%0 of 27
=637PhayaoPhayao, Thailand 0%0 of 30
=637MagongTaiwan, Taiwan 0%0 of 30
=637DaejeonDaejeon, South Korea 0%0 of 30
=637Wodzisław ŚląskiSilesia, Poland 0%0 of 30
=637VigoGalicia, Spain 0%0 of 30
=637Irapuatolast full day 11 OctGuanajuato, Mexico 0%0 of 25
=637Celayalast full day 11 OctGuanajuato, Mexico 0%0 of 22
=637BoseongJeollanam-do, South Korea 0%0 of 28
=646PrešovPrešov Region, Slovakia 0%0 of 28
=646HonmachiKumamoto, Japan 0%0 of 30
=646GyőrGyőr-Moson-Sopron, Hungary 0%0 of 30
=646São PauloSão Paulo, Brazil 0%0 of 30
=646Little RockArkansas, United States 0%0 of 30
=646MurraysvilleNorth Carolina, United States 0%0 of 30
=652WawerMazovia, Poland 0%0 of 30
=652Taesal-liChungcheongnam-do, South Korea 0%0 of 27
=652HwawŏnDaegu, South Korea 0%0 of 29
=652MariglianoCampania, Italy 0%0 of 29
=652YeongamJeollanam-do, South Korea 0%0 of 30
=657Nong Bua LamphuNong Bua Lamphu, Thailand 0%0 of 30
=657SintansinDaejeon, South Korea 0%0 of 29
=657KwangyangJeollanam-do, South Korea 0%0 of 30
=657PłockMazovia, Poland 0%0 of 30
=657ItaquaquecetubaSão Paulo, Brazil 0%0 of 30
=657León de los AldamaGuanajuato, Mexico 0%0 of 27
=657MaderaCalifornia, United States 0%0 of 30
=664Voluntarilast full day 10 OctIlfov, Romania 0%0 of 27
=664Konstancin-JeziornaMazovia, Poland 0%0 of 30
=664BuyeoChungcheongnam-do, South Korea 0%0 of 28
=664Ōyanomachi-noboritateKumamoto, Japan 0%0 of 28
=664WabuGyeonggi-do, South Korea 0%0 of 29
=664HavířovMoravian-Silesian Region, Czechia 0%0 of 30
=664Salamancalast full day 11 OctGuanajuato, Mexico 0%0 of 25
=664ChangnyeongGyeongsangnam-do, South Korea 0%0 of 29
=672Holbocalast full day 10 OctIași County, Romania 0%0 of 21
=672Baia MareMaramureş, Romania 0%0 of 24
=672Buri RamBuriram, Thailand 0%0 of 30
=672DaeguDaegu, South Korea 0%0 of 30
=672SokchoGangwon-do, South Korea 0%0 of 30
=672PohangGyeongsangbuk-do, South Korea 0%0 of 30
=672Gyeongsan-siGyeongsangbuk-do, South Korea 0%0 of 30
=672GwangjuGyeonggi-do, South Korea 0%0 of 29
=672HwadoGyeonggi-do, South Korea 0%0 of 29
=672DakarDakar, Senegal 0%0 of 30
=672ComoLombardy, Italy 0%0 of 23
=672ZapopanJalisco, Mexico 0%0 of 28
=672Somerset Westlast full day 8 OctWestern Cape, South Africa 0%0 of 25
=685ChaniáCrete, Greece 0%0 of 29
=685AcharnésAttica, Greece 0%0 of 23
=685RuseRuse, Bulgaria 0%0 of 30
=685BiałystokPodlasie, Poland 0%0 of 30
=685PhraePhrae, Thailand 0%0 of 30
=685GimcheonGyeongsangbuk-do, South Korea 0%0 of 30
=685ŌzuKumamoto, Japan 0%0 of 30
=685HitaOita, Japan 0%0 of 30
=685NamyangjuGyeonggi-do, South Korea 0%0 of 30
=685GrazStyria, Austria 0%0 of 30
=685TepliceÚstí nad Labem Region, Czechia 0%0 of 30
=685KladnoCentral Bohemia, Czechia 0%0 of 30
=685Leccolast full day 11 OctLombardy, Italy 0%0 of 28
=685FontanaCalifornia, United States 0%0 of 30
=685OwariasahiAichi, Japan 0%0 of 30
700WarsawMazovia, Poland 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).