Air quality in Singapore deteriorated through the night and by Saturday afternoon every region of the island was recording 24-hour Pollutant Standards Index (PSI) readings in the unhealthy band, according to CNA. The 24-hour PSI stood between 109 and 151 at 6pm, with the western part of the country registering the highest figure.
The National Environment Agency (NEA), in its evening advisory, projected that Sunday's 24-hour PSI would fall between 80 and 130 — a spread that straddles the moderate and unhealthy categories. CNA reported the overnight decline in air quality.
Why it matters
The haze affects daily life well beyond the discomfort of a hazy skyline. NEA's guidance asks the public to plan outdoor activity around the 24-hour PSI forecast and to consult the latest one-hour PM2.5 figures before heading outside at short notice. Those recommendations carry particular weight for children, older people, pregnant women and anyone living with a chronic heart or lung condition.
The episode also lands at a moment when Singapore is testing its legal tools against the companies suspected of contributing to the fires behind the smoke, making this haze spell as much a governance story as an environmental one.
Where the readings stood
Hourly PM2.5 concentrations, which measure fine particles and respond faster to changing conditions than the 24-hour PSI, were raised across the island earlier on Saturday. By 6pm they had returned to the normal band in the central and northern regions, at 52 and 37 respectively, CNA reported.
The picture was less even elsewhere. The west posted the highest one-hour PM2.5 reading of the day at 93, the south recorded 88 and the east 58. Those figures indicate that conditions varied considerably by location even as the island-wide 24-hour index sat in unhealthy territory.
For immediate outdoor plans, NEA advises that when hourly PM2.5 concentrations are in the elevated band, healthy people should cut back on strenuous activity for the following hour, while vulnerable groups should steer clear of it altogether. For Saturday's activities more broadly, the agency asked healthy individuals to reduce prolonged or strenuous outdoor exertion, urged the elderly, pregnant women and children to keep such activity to a minimum, and said those with chronic heart or lung disease should avoid it.
Showers and a wind shift in the forecast
NEA expects winds to come from the southwest or west, a direction it said could restrict the movement of smoke haze toward Singapore. Rain forecast over the island and the surrounding area may also ease conditions, the agency added.
Those winds are projected to hold from the southwest or west into Monday and Tuesday. "With showers expected over Singapore and the vicinity, the haze situation is likely to improve," NEA said, according to CNA.
The advisory follows a fluctuating few days. On Friday morning, PM2.5 levels across Singapore were reported to be normal, with thundery showers forecast for the afternoon, according to AsiaOne. Yahoo News Singapore later reported that PM2.5 readings had climbed back into the elevated range after overnight improvements. The Straits Times reported that visitors to Singapore were wearing masks and adjusting their plans, with some tour operators noting a drop in bookings.
Enforcement efforts gather pace
The return of the haze coincides with a sharper enforcement push. On Friday, NEA served notices on 10 companies based in Singapore under the Transboundary Haze Pollution Act — the first occasion it has used the law since it took effect, CNA reported. The firms operate in the palm oil or forestry sectors and have been instructed to supply details of their corporate relationships, their land concessions in Indonesia, and the steps they have taken to prevent and combat fires.
The agency is also pursuing additional information from 10 Indonesian companies that received notices during the previous week.
In a separate move, the Ministry of Law set out plans for a specialist panel drawing on legal, audit and investigative firms to scrutinise companies that may be connected to the haze. The panel is intended to trace corporate structures, supply chains and cross-border business relationships, helping establish whether any company caused or condoned the fires.
What to watch
Sunday's PSI readings will show whether the expected showers and southwesterly winds deliver the improvement NEA anticipates, while the responses to the notices will indicate how quickly the enforcement effort moves from information-gathering to action.
