10 Most Polluted Regions in Indonesia Tonight (Jan 4)

Air quality in Riau tonight is the worst in Indonesia. Based on the Air Pollutant Standard Index (ISPU) page of the Ministry of Environment and Forestry (KLHK) on Sunday (Jan 4, 2026) at 6:00 PM WIB, it was revealed that Riau's air quality index was 100.

According to the KLHK's Directorate of Air Pollution Control, ISPU is a unitless number used to describe ambient air quality conditions at a specific location, based on its impact on human health, aesthetic value, and other living things.

ISPU calculations are based on measurements of seven air pollutant parameters: PM10, PM2.5, NO2, SO2, CO, O3, and HC. Air pollutant parameter measurements are distributed across 72 stations in various regions.

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Based on Ministry of Environment and Forestry Regulation No. 14 of 2020 concerning the Air Pollutant Standard Index, an ISPU range of 0-50 indicates good air quality, 51-100 indicates moderate air quality, and 101-200 indicates unhealthy air quality that is harmful to humans, animals, and plants.

Furthermore, very unhealthy air quality in the 201-300 range can increase health risks for sensitive groups. Meanwhile, hazardous air quality above 300 can seriously harm health and requires prompt action.

Below Riau, Aceh ranks second worst in Indonesia with an air quality index of 99. Then, in third place is South Sumatra with an air quality index of 96.

This means no region has hazardous air quality.

Here is a list of the 10 provinces with the worst air quality index in Indonesia on Sunday, January 4, 2026, at 6:00 PM WIB.

1. Riau: 100

2. Aceh: 99

3. South Sumatra: 96

4. Banten: 95

5. Jambi: 92

6. West Sumatra: 87

7. North Sumatra: 83

8. North Sumatra: 81

9. Lampung: 74

10. Central Kalimantan: 70

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