THAT familiar acrid smell and light foggy blanket - your senses have not deceived you.
The haze returned to Singapore yesterday after a lengthy reprieve, and the National Environment Agency (NEA) is forecasting more of it today.
"Slightly hazy conditions are expected for Singapore, and the overall air quality... is expected to fluctuate between the high end of the moderate range and the low end of the unhealthy range," it said yesterday.
Healthy people should reduce prolonged or strenuous outdoor physical exertion, it said. Elderly people, pregnant women and children should minimise such activity, while those who do not feel well or have chronic lung or heart conditions should avoid it.
The NEA said the pollution's return was due to hot spots in South Sumatra detected over the past week. Satellite coverage picked up a sharp spike in hot spots in Sumatra, with the count rising from close to zero last Monday to almost 300 last Friday.
With wind blowing the haze into Singapore, the 24-hour Pollutant Standards Index (PSI) crossed 100 into the "unhealthy" range at 6am in the west yesterday - the first time it had done so anywhere on the island since April. The index was revised in April to more directly account for small, toxic particles called PM2.5.
With air quality in the west remaining slightly unhealthy for most of yesterday and "moderate" for the rest of Singapore, droves of Singaporeans turned to the NEA's website for updates.
The high volume of traffic caused access to the website to become intermittent, and the NEA later apologised on its Facebook page for any inconvenience.
Writing on the social media site yesterday, Minister for the Environment and Water Resources Vivian Balakrishnan said the NEA had urged the Indonesian authorities to take action last week. "We also stand ready to provide assistance if necessary," he wrote, adding that he had "watched overnight with some concern as the change in wind direction brought haze... to Singapore".
Residents and shopkeepers in the west said they would wait for the haze to worsen before getting protective N95 face masks ready.
"We still have the masks at home, but it's not so bad yet. I'm just worried about what will happen if the haze becomes worse during the school exams," said sales assistant Agnes Chew, 36, who has a daughter in primary school.
Last month, Singapore passed a transboundary haze law to punish firms that cause fires overseas which lead to haze here. A company can be fined up to $100,000 for every day of haze Singapore suffers. It can also be fined up to $50,000 for each day it does not comply if Singapore has served notice on it to act to prevent haze here. If convicted, the maximum combined penalty is $2 million.