KUALA LUMPUR, Oct. 24 -- Air quality deteriorated across several states this morning, with 21 monitoring stations breaching unhealthy thresholds on the Air Pollutant Index (API), according to the Department of Environment (DOE).

Data from the DOE's environmental monitoring dashboard at 10.00am showed that nearly a third of the country's 68 air quality stations registered readings between 101 and 200.

Another 41 stations recorded moderate air quality, while only six maintained good air levels. No location breached very unhealthy or hazardous benchmarks, and all monitoring stations remained fully operational online.

Southern states bore the brunt of the smog, accounting for the country's highest pollution levels. Seremban in Negeri Sembi...