Dietmar Rabich · CC BY-SA 4.0 · cropped
Air quality in central Singapore returned to the unhealthy range at 11am on Saturday, October 3, with a 24-hour Pollutant Standards Index (PSI) of 102, AsiaOne reported, after two days of better readings. The National Environment Agency (NEA) forecasts the 24-hour PSI to stay between moderate and low unhealthy.
For visitors, the decision is how much of a day to plan outdoors, not whether to fly. Anyone landing at Changi Airport can still expect normal arrivals, because none of the reports reviewed describe flight disruption in Singapore, but outdoor tours, runs and long walks deserve a plan B.
- Trigger: central Singapore 24-hour PSI reached 102 at 11am on October 3, with the unhealthy range starting at 101.
- Other regions: east 94 and west 91 at the same reading, both still moderate.
- Source of smoke: fires in southern Sumatra and Kalimantan, Indonesia, per NEA.
- NEA outlook: moderate to low unhealthy, with dry weather forecast for Saturday.
- Immediate check: the one-hour PM2.5 reading, which was elevated at 66 in the east and 63 in central Singapore.
Central Singapore Crosses PSI 100
AsiaOne said the 11am PSI ranged from 76 to 102 across the island, with central Singapore the highest. PSI readings from 101 to 200 count as unhealthy, so the central region sits just over the line while the east and west remain moderate.
The one-hour PM2.5 figure moves faster than the daily index. AsiaOne put it in the elevated band for both the east and central regions, which is the number NEA tells the public to use before stepping out for exercise or a long outdoor stretch.
Sumatra and Kalimantan Smoke Keeps Returning
NEA’s Friday evening update, as described by AsiaOne, said moderate to dense smoke plumes from southern Sumatra were drifting toward Singapore, with more smoke seen from fires in Kalimantan. Dry weather and southeasterly or southerly winds on Saturday could carry that smoke across the strait.
This is not a one-day event. Malay Mail reported on September 19 that central Singapore PSI hit 107, calling it the first significant haze since October 2023, and NEA’s September 29 update logged a 24-hour PSI of 107 to 157 in the unhealthy range, with a forecast of high moderate to mid unhealthy.
Rain helps. NEA’s September 30 update noted an improvement after showers, with the 24-hour PSI at 91 to 112 and one-hour PM2.5 down to 6 to 18. Readings climbed again once the showers passed.
NEA Health Guidance at Unhealthy Levels
NEA’s health advisory splits guidance by group. Healthy people should reduce prolonged or strenuous outdoor exertion when the 24-hour PSI is unhealthy, while the elderly, pregnant women and children should minimise it.
People with chronic lung or heart disease should avoid prolonged or strenuous outdoor exertion at unhealthy levels. NEA also says to use the one-hour PM2.5 for immediate plans and the 24-hour PSI forecast for next-day planning.
Borneo Airports Face the Worst Visibility
The fires are far from Singapore, and the closer to them, the worse the travel effects. AP reported on September 14 that thick smoke had disrupted flights for several days in Indonesia’s West Kalimantan, with visibility in Pontianak below one kilometer.
Tempo reported on September 2 that AirNav Indonesia saw visibility drop to 600 meters at Pontianak, delaying all flights there and forcing a Jakarta flight to return to its origin. Those are Indonesian airport conditions, not Singapore ones, but they show why trips to Borneo carry more flight risk than a stopover in Singapore.
| If you… | What to do |
|---|---|
| Have a morning run or long walking tour booked in central Singapore | Check the one-hour PM2.5 reading before leaving and shorten or move the session indoors if it is elevated. |
| Travel with young children, older relatives or anyone with lung or heart conditions | Follow NEA’s stricter guidance and keep outdoor time minimal while the PSI is unhealthy. |
| Fly into Changi this weekend | Expect normal operations based on the reports reviewed, and confirm your flight status with the airline as usual. |
| Plan onward flights to Kalimantan or other Indonesian Borneo cities | Allow extra buffer, since smoke has cut visibility and delayed flights there in September. |
Sunday, October 4 is the next check. NEA publishes a daily haze situation update, so read the evening forecast before booking outdoor activities for the following day.
Any shower day is the relief window. The September 30 improvement followed rain, but the haze returned within days, so treat a clear morning as temporary.
Before any Borneo connection is the flight check. Confirm departure status with your airline on the morning you fly, because visibility at Indonesian airports can change within hours.
Is the air in Singapore unhealthy on October 3?
Yes in central Singapore, where the 24-hour PSI reached 102 at 11am, but the east and west were still moderate at 94 and 91.
Which reading should I use to plan my day?
NEA says to use the one-hour PM2.5 for immediate outdoor activities and the 24-hour PSI forecast to plan ahead.
Are flights at Changi affected by the haze?
None of the reports reviewed describe flight disruption in Singapore, so check your airline for your own flight.
Where is the smoke coming from?
NEA points to fires in southern Sumatra and Kalimantan in Indonesia, carried toward Singapore by prevailing winds.
