Smog in Bangkok is expected to worsen through Monday due to persistently poor air dispersion, with five districts reporting unsafe levels of fine-dust pollution on Saturday. The average concentration of particulate matter 2.5 micrometres or less in diameter (PM2.5) in the capital stood at 31.5 microgrammes per cubic metre (µg/m³) at 11am, according to the Bangkok Air Quality Information Centre (AirBKK) website.The average reading at 7am was 29.2µg/m³, up from 21.