The sky may occasionally turn hazy over Singapore today, with the 24-hour Pollutant Standards Index (PSI) fluctuating between the high end of moderate and the low end of the unhealthy range, the National Environment Agency (NEA) warned yesterday evening.
Thundery showers are also forecast in the late morning and early afternoon.
The skies were grey yesterday as Singapore experienced hazy conditions from early morning. At 1pm, the 24-hour PSI was at 80-87, which is within the moderate range. At 8pm, it had increased slightly to 82-94. Air quality is considered unhealthy when the index crosses 100.
The haziness is due to the spread of smoke haze from Sumatra under weakening wind conditions over Singapore. The number of hot spots detected on the Indonesian island decreased to 111 yesterday from 395 the day before, the NEA said.
Conditions will improve should wind speeds pick up, though the haze situation in Singapore may also deteriorate if the prevailing winds shift and blow from the south or south-west.
NEA chief executive Ronnie Tay wrote to his Indonesian counterpart three days ago to register Singapore's concern over the situation and to seek an urgent update on the ground situation in Sumatra.
The agency also repeated Singapore's offer of an assistance package to help combat the haze problem there.
NEA first contacted Indonesia two weeks ago in view of the deteriorating hot spot situation in Sumatra then, and said it would continue to be in touch going forward.
Given the haze forecast, people here are advised to reduce outdoor activities and physical exertion, to limit the ill effects from haze exposure. The NEA added that the elderly, children and pregnant women should minimise prolonged or strenuous outdoor physical exertion, while those with chronic lung or heart disease should avoid such activities.
Those who are not feeling well, especially the elderly and children, and those with chronic heart or lung conditions, should seek medical attention.