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How Singapore’s air quality changed on September 20, 2026
At 6am on September 20, the 24 hour PSI was unhealthy in central Singapore (123), the east (102) and the west (105). NEA reported smoke plumes from fires in Kalimantan and Sumatra and forecast a moderate to low unhealthy 24 hour PSI.
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Key takeaways
- At 6am on September 20, the 24 hour PSI was unhealthy in central Singapore (123), the east (102) and the west (105).
- NEA reported smoke plumes from fires in Kalimantan and Sumatra and forecast a moderate to low unhealthy 24 hour PSI.
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openai.comCreate a landscape editorial hero image for this Studio Global article: How did Singapore’s air quality change during the haze on Sep 20, 2026—including the central, eastern and western regions’ 24-hour PSI readi. Article summary: Singapore’s haze pushed the central, eastern and western regions into the *unhealthy* 24-hour PSI band on the morning of September 20, 2026. The east and west returned to *moderate* by the afternoon; the central region f. Topic tags: general, general web. Style: premium digital editorial illustration, source-backed research mood, clean composition, high detail, modern web publication hero. Use reference image context only for broad subject, composition, and topical grounding; do not copy the exact image. Avoid: logos, brand marks, copyrighted characters, real person likenesses, fake screenshots, UI text, readable text, watermarks, charts with fake numbers, clic
Singapore’s haze eased over September 20, 2026, but the improvement was uneven. The east and west were back in the moderate 24-hour Pollutant Standards Index (PSI) range by early afternoon; central Singapore remained unhealthy until the evening. 3
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How the PSI changed during the day
At 6am, the 24-hour PSI stood at 123 in central Singapore, 102 in the east and 105 in the west—all above the unhealthy threshold of 100. Central Singapore had crossed into the unhealthy range the previous afternoon. 2
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By 1pm, the east had fallen to 87 and the west to 97, both moderate. Central Singapore was still unhealthy at 107. Its reading reached 100 at 7pm, bringing all regions back into the moderate range. Singapore classifies a 24-hour PSI of 51–100 as moderate and 101–200 as unhealthy. 3
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What the morning readings say—and do not say—about the races
The 24-hour PSI and the one-hour PM2.5 reading describe different time periods. At 9am, one-hour PM2.5 readings were in the normal band across all five regions, even though some 24-hour PSI readings were unhealthy. 6 That contrast provides context for outdoor activity decisions, but the available sources do not identify the two races or document their organisers’ reasons for proceeding. It would be misleading to attribute those decisions to the PM2.5 readings alone.
What NEA reported and forecast
In its September 20 update, the National Environment Agency (NEA) reported moderate to dense smoke plumes from fires in Kalimantan and southern and central Sumatra. It also observed smoke haze from Sumatra drifting towards Singapore. At 5pm, NEA put the 24-hour PSI across Singapore at 71–102, spanning the moderate and unhealthy ranges, and forecast a moderate to low-unhealthy 24-hour PSI. 4
The evening return to moderate readings therefore described conditions at that time, not a guarantee that haze would stay below the unhealthy threshold. 4
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What is the short answer to "How Singapore’s air quality changed on September 20, 2026"?
At 6am on September 20, the 24 hour PSI was unhealthy in central Singapore (123), the east (102) and the west (105).
What are the key points to validate first?
At 6am on September 20, the 24 hour PSI was unhealthy in central Singapore (123), the east (102) and the west (105). NEA reported smoke plumes from fires in Kalimantan and Sumatra and forecast a moderate to low unhealthy 24 hour PSI.