KUALA LUMPUR, Sept. 18 -- Air quality across Malaysia deteriorated significantly this morning, with 34 monitoring stations nationwide recording "Unhealthy" Air Pollutant Index (API) levels as of 8.30am, according to Department of Environment (DoE) data.

Readings across the country spanned between 104 and 198, indicating widespread haze coverage across both Peninsular Malaysia and Sarawak.

Johan Setia in Selangor recorded the nation's worst air quality at 198, hovering just two points shy of the 200 mark that triggers a "Very Unhealthy" classification.

The next four most severely affected locations were concentrated heavily in Sarawak and the central-southern peninsula: Kuching (192), Samarahan (184), Nilai in Negeri Sembilan (181), and...