North Sumatra Air Pollution at Night (April 13) is the Worst in Indonesia

North Sumatra's air quality tonight is the worst in Indonesia. Based on the Air Pollution Standard Index (ISPU) page of the Ministry of Environment and Forestry (KLHK) on Monday (April 13, 2026) at 6:00 PM WIB, it was revealed that the air quality index in North Sumatra is 321.

According to the KLHK Air Pollution Control Directorate, ISPU is a unitless number used to describe ambient air quality conditions at a specific location and is based on impacts on human health, aesthetic values, and other living beings.

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

(Read: List of Provinces Hit by Floods and Landslides in Early 2026)

Based on KLHK Regulation No. 14 of 2020 concerning the Air Pollution Standard Index, ISPU in the 0-50 range means good air quality, 51-100 means moderate air quality, and 101-200 means unhealthy air that is harmful to humans, animals, and plants.

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

Below North Sumatra, West Java ranks second worst in Indonesia with an air quality index of 102. Then, Riau ranks third with an air quality index of 97.

This means North Sumatra has hazardous air quality.

Here is the list of 10 provinces with the worst air quality index in Indonesia on Monday, April 13, 2026 at 6:00 PM WIB.

1. North Sumatra: 321

2. West Java: 102

3. Riau: 97

4. South Sumatra: 92

5. West Sumatra: 87

6. DKI Jakarta: 85

7. Jambi: 83

8. Banten: 81

9. South Sulawesi: 79

10. East Kalimantan: 78

(Read: List of Provinces Hit by Floods and Landslides in Early 2026)