KUALA LUMPUR, Sept 21 — Air quality in Kapit, Sarawak, deteriorated steadily throughout the day, overtaking other hotspots to become the most polluted location in Malaysia as of 4pm today.

According to Department of Environment (DoE) data, Kapit recorded an Air Pollutant Index (API) reading of 173, climbing from 166 logged at 8.30am.

Nationwide, a total of 17 monitoring stations remained in the “Unhealthy” bracket (API 101 to 200), down from the 21 affected stations reported earlier in the morning.

IPD Serian in Sarawak, which held the morning’s highest reading at 168, remained unchanged in the afternoon to rank second nationally. Sibu and Sri Aman followed jointly at 163, with Sibu registering a sharp increase from 156 earlier in the day.

Sarawak accounts for majority of affected areas

Sarawak remained by far the hardest-hit state, accounting for 10 of the 17 unhealthy stations nationwide.

Beyond the top four hotspots, elevated pollution levels were recorded in Bintulu (161), Samalaju (158), Kuching (157), Samarahan (155), and Miri (153). Sarikei was the sole station in the state below the 150 mark, registering 106.

In the Klang Valley, Cheras in Kuala Lumpur recorded 156, the highest reading in Peninsular Malaysia, closely followed by Putrajaya at 155. Both stations showed minimal variation from morning levels.

Negeri Sembilan also remained in the unhealthy range, though readings eased slightly, with Nilai at 155 (down from 158) and Seremban at 152 (down from 155).

In Sabah, Politeknik Kota Kinabalu registered 151, a slight improvement from 153 in the morning.

Improvements in Selangor

Selangor recorded the most significant improvement of the day. Johan Setia saw its API drop from 153 to 124, while Shah Alam improved from 152 to 120, though both remained within the unhealthy threshold.

Several stations across the country improved sufficiently to exit the unhealthy category entirely by 4pm, including Kota Kinabalu city in Sabah, Bukit Rambai in Melaka, Tangkak in Johor, alongside ILP Miri and Limbang in Sarawak.

The DoE confirmed that round-the-clock air quality surveillance remains active nationwide, advising the public, especially vulnerable groups, to limit outdoor activities and monitor real-time updates as wind and hotspot patterns shift.