A post on the r/singapore subreddit dated 14 October 2026 claimed that Singapore has been the “most polluted city for 6 consecutive days”. The post shared a line chart with plots for daily US Air Quality Index (AQI) readings for Beijing, Hanoi, Kuala Lumpur, Kuching, Medan, Mumbai, New Delhi and Singapore from 1 to 14 October. Singapore’s grey line sits above the other seven cities from 9 to 14 October, ending at a reading of 298.
Singapore is currently experiencing a severe haze season. According to IQAir data reported by The Nation, Singapore’s air quality has been in the “unhealthy” range on the US AQI since 4 October. On 9 October, the same weekend as the Singapore Grand Prix, IQAir recorded an AQI of 209 in Singapore, which falls in the “very unhealthy” range. On the National Environment Agency’s Pollutant Standards Index (PSI), a 24-hour rolling average, the reading in the west hit a season high of 230 on 18 October, also in the “very unhealthy” range. The haze is driven by forest and peatland fires in Sumatra and Kalimantan, which Reuters described as Indonesia’s most intense in 11 years. According to the ASEAN Specialised Meteorological Centre, the two regions had recorded 38,511 hotspots as of 13 October, the highest in a decade. Experts have linked the dry conditions to a strong El Nino weather pattern, which results in spikes in global average surface temperature, and the Meteorological Service of Singapore expects the shift to the wetter monsoon season only in late October or early November.
When we looked at the claim, we found that it is supported by multiple news reports. The rankings in question come from IQAir, a Swiss air quality technology company that publishes a live ranking of major cities by US AQI. On 7 October, Singapore overtook Kuala Lumpur to become the most polluted city on the ranking, with air quality rated “very unhealthy” that afternoon. Malaysian outlet SAYS reported an AQI of 211 for Singapore at the time, up from 166 earlier that day, when it ranked fifth. On 12 October, AFP reported that Singapore again ranked as the world’s most polluted city on IQAir, and a later version of the same wire story put Singapore’s AQI at 191 that day. Early on 13 October, The Jakarta Post reported that Singapore ranked among the two most polluted major cities on the list.
There is a catch, however: the IQAir rankings cover only 120 major global cities. When we investigated the AQI of cities in Indonesia on 19 October, where one would expect pollution to be highest given the forest and peatland fires, we found that parts of Kalimantan recorded AQIs of up to 538, much higher than Singapore’s which was 154.
In summary, it is true that Singapore topped IQAir’s real-time ranking of the world’s most polluted major cities on 6 consecutive days in October 2026, as confirmed by AFP, the South China Morning Post and other outlets. The haze behind it is real and severe, and it is driven by fires in Indonesia.
That said, IQAir’s list represents only major cities, so it does not mean Singapore had the worst air anywhere in the world. Our independent check found that areas like Kalimantan, where the forest fires originated, recorded AQIs on 19 October that were much higher than Singapore’s. However, we were unable to check the AQIs for these areas from 9 to 14 October. Therefore, we rate this claim as likely false.
