Air quality in central Singapore back in unhealthy range

SINGAPORE: Air quality in Singapore dipped back into the unhealthy range on Monday (Sep 14), after four days of moderate readings, as hotspots and haze persisted in parts of Indonesia.The 24-hour Pollutant Standards Index (PSI) in Singapore's central region rose to 102 at noon, while readings in the other four regions ranged from 79 to 91.In an update on Monday, the National Environment Agency (NEA) said it was closely monitoring air quality across Singapore.It said dry conditions had been observed across the southern Association of Southeast Asian Nations (ASEAN) region on Monday morning, except for showers over parts of Sumatra. Hotspots were detected in southern Sumatra, as well as western, central and southern Kalimantan."A few hotspots were also detected in peninsular Malaysia and Java," NEA said, adding that moderate to dense haze had been observed in central and southern Sumatra, as well as western and central Kalimantan.Transboundary haze was also observed in parts of Sarawak, peninsular Malaysia and southern Vietnam, with air quality monitoring stations in the affected areas reporting moderate to unhealthy readings.The 24-hour PSI spiked into the unhealthy range in central Singapore on Sep 4 for the first time since 2023, prompting NEA to start providing daily haze advisories from that evening.The unhealthy PSI band runs from 101 to 200, while a reading is considered "very unhealthy" if it is between 201 and 300, and "hazardous" if it is above 300.