SINGAPORE — After the haze had seemingly moderated over the weekend, it came back with a vengeance yesterday, shrouding the city throughout the day, affecting visibility and causing respiratory problems for some, as the air quality plunged to unhealthy levels for the first time in almost three years.

At 3pm, the three-hour Pollutant Standards Index (PSI) reading reached 105, which falls within the “unhealthy” range. The situation deteriorated rapidly and at 10pm, the three-hour PSI was 155 — the highest since September 1997 when it reached 226. The last time the haze hit such levels was in 2006, when the PSI peaked at 150. At press time, the reading was 145.

The poor air quality prompted the Ministry of Manpower to remind employers to minimise outdoor work involving strenuous activities and put in place a system that regularly updates their workers on the measures being taken to ensure their safety and well-being, and allow employees to report any adverse effects on their health.

Under existing guidelines, uniformed services such as the Singapore Armed Forces (SAF) and Singapore Civil Defence Force (SCDF) are also to reduce physical and outdoor training.

Ministry of Defence Director of Public Affairs Kenneth Liow said: “The health and safety of our servicemen are of paramount importance to the SAF. We monitor air quality closely, and have in place a set of PSI-Activity Guidelines under the SAF Medical Directives and Training Safety Regulations to calibrate our outdoor activities and training according to the PSI reading.”

An SCDF spokesperson said that in addition to the guidelines, “officers will exercise discretion to suspend training when deemed necessary in view of the haze situation at their location”.

The National Environment Agency (NEA) attributed the haze to drier weather conditions, which led to “an escalation in hotspot activities” in parts of Sumatra in Indonesia, adding that the situation was expected to persist over the next few days.

On Saturday and Sunday, 101 and 138 hotspots were detected respectively. Yesterday, another 113 hotspots were detected.

Minister for Environment and Water Resources Vivian Balakrishnan said in a press statement that the Government was “deeply concerned” about the latest number of hotspots in Sumatra which have “led to such a bad haze” here. “We are in touch with the Indonesian authorities to register our concern, and renew our offer of assistance. I will also speak to the Indonesian Minister for the Environment personally to convey the seriousness of the situation,” he said.

NEA also said that it has alerted Indonesia’s Ministry of Environment “on the haze situation experienced in Singapore, and urged the Indonesian authorities to look into urgent measures to mitigate the transboundary haze occurrence”. It added that it will “continue to monitor the situation closely and provide further updates when necessary”.

Given the hazy conditions, the NEA has advised children, the elderly and those with heart or lung diseases, to “reduce prolonged or heavy outdoor activities. Everyone else should limit prolonged or heavy outdoor activities”.

Daily routines affected, GPs seeing more patients

Barclays economist Wai Ho Leong noted that the economic cost for Singapore can be “significant” if the haze persists, particularly in the services sector. “It could cast a pall on the Great Singapore Sale and divert would-be visitors to other parts of the world,” he told Bloomberg. Nevertheless, the effect of the haze was already felt by many on the island.

Deliveryman Lim Keng Hua, 50, said that visibility inside the Chin Swee Tunnel - where he was driving through yesterday afternoon - was “poor”. “I could not even see the lane markers,” he added.

The haze was the talk of town yesterday as the topic trended on social media with many netizens lamenting its adverse effects and sharing pictures of the hazy skies on social networking sites such as Facebook, Twitter and Instagram.

While the haze disrupted some people’s daily routines - as they chose to stay indoors - there were others who carried on their activities. For instance, when TODAY visited MacRitchie reservoir yesterday afternoon, some students were spotted undergoing their Co-Curricular Activity trainings during the school holidays - despite the Ministry of Education’s existing guidelines that outdoor physical education, sports and games are to be cancelled once the PSI reading hits the unhealthy range. Nevertheless, the teachers overseeing the trainings said that the students would not be asked to do any strenuous activity. One of them noted that they would exercise their own judgement on whether the training should be cancelled.

Still, canoeist Lum Tze Tian, a 23-year-old Nanyang Technological Undergraduate, abandoned his plans to train because of the haze. “I also advised my juniors to stop training because the situation is quite bad,” he said.

Some general practitioners whom TODAY spoke to also reported seeing more patients with haze-related ailments.

Noting the difficulty of identifying patients who are suffering ailments caused solely by the haze, Dr Choong Sheau Peng said that he has recently been seeing “about six to eight more cases per day” of patients who have asthma and skin problems.

Another GP, Dr Victor Teo, noted that conditions such as eczema, asthma and eye irritations- including like conjunctivitis- have been made worse by the haze. The proportion of patients with such issues has increased over the past one week.”