But if things get worse, and the PSI hits extremely dangerous levels, the NEA and the Health Ministry will put in place a haze action plan. The Environment and Water Resources Ministry has also given the assurance that a standard operating procedure is already in place if the situation worsens.

 
Said Senior Parliamentary Secretary for the Environment and Water Resources Ministry Dr Amy Khor: "The MOH (Ministry of Health) has plans, for instance, making sure there are masks available and getting the polyclinics and hospitals and GPs ready. So there are contingency plans. In fact, the NEA and MOH have been meeting regularly on this issue.

Yesterday, according to the NEA, visibility dropped from 2-3km to just 1-2km. Normal visibility is 10km.

For now, the problem at Changi has not been severe enough to cause flights to be delayed or cancelled. But Singapore's neighbours have had it much worse.

Flights were cancelled over at the province of Jambi in Sumatra, Indonesia, as the smoke from more than 100 fires caused visibility to dip to just 50 metres, resulting in government officials closing the airport due to safety concerns.

At the Kuala Lumpur International Airport, general visibility was down from 10km to just 4km, while the level at Johor's Senai airport was down to 2.5km. Both reported that air traffic had not been affected so far.

In the eyes of many Singaporeans, however, the haze — caused by Indonesia's annual burn-off to clear land for agriculture — is fast becoming Public Enemy No 1.

Businessman James Goh, 31, used to run at the West Coast Park at least thrice a week, but for the past fortnight he has limited his exercise to jogging on a treadmill. Not everyone has the luxury to remain indoors, though. Operations executive David Ong, 45, works in the construction line and has to conduct numerous site visits during the day. "It's becoming quite alarming as I have a history of asthma and bronchitis and I can feel my throat getting dryer," he said. "How much longer do we have to put up with this?"

The NEA has maintained its health advisory issued over the weekend, with the prevailing south-easterly winds bringing in smoke haze from fires in Kalimantan.

Yesterday, Singaporeans woke up to a PSI of 86 at 6am, with the level inching its way up to 114 at 2pm before peaking at 130 at 5pm. The PSI eased to 113 by 8pm and 92 at 10pm. The 24-hour PSI reading taken at 4pm was 98. A reading of between 101 to 200 is considered "unhealthy", with Oct 7 seeing the highest PSI this year, with the index hitting 150.

Meanwhile, doctors are seeing more patients complaining of haze-related symptoms.

At the Killiney Family and Wellness Clinic, general practitioner Dr Clarence Yeo said the number of such patients has gone up by 25 per cent. Demand for protective face masks has also seen a marked increase, he said.

"We're seeing all kinds of cases, ranging from those with asthma and respiratory problems, to eye irritations, to rashes and even headaches. It's not surprising and if the haze continues, the number of cases will increase," he told Today.

The NEA has urged the general public to curb any outdoor vigorous activities, while those with heart and respiratory ailments should refrain from physical exertion and going outdoors.

According to latest satellite pictures provided by the NEA, there were a total of 24 hotspots in Sumatra and 197 hotspots in Kalimantan were detected, with many areas in Kalimantan obscured by smoke haze.

For updates on the haze situation, visit www.nea.gov.sg/psi or call 1800-225 5632.