The situation is being exacerbated by the strengthening El Nino weather pattern, which causes drier weather in much of the region.

Singapore was shrouded in haze on Tuesday, with smoke from wildfires in neighboring Indonesia raising islandwide pollution to levels that pose a health risk. 

All five regions of the city-state recorded unhealthy air-quality levels, the first time that’s happened since September 2019, according to the National Environment Agency. Singapore’s air currently ranks among the 10 most polluted cities in the world, according to IQAir data, with the capitals of Malaysia and Indonesia also among the top spots.

Indonesia often battles wildfires during its annual dry season, but hotspots this year have been higher than normal. There were more than 9,000 recorded in August, the most for the month in data going back to 2015, and more than 7,000 have been recorded so far in September, according to the Forestry Ministry’s fire-monitoring platform SiPongi.

The situation is being exacerbated by the strengthening El Nino weather pattern, which causes drier weather in much of the region. Little immediate relief is expected from the weather, with dry conditions expected to persist across much of the south of Southeast Asia in the near term, according to the ASEAN Specialised Meteorological Centre. 

“The hotspot and haze situation in the region is expected to remain escalated with a continued risk of transboundary smoke haze,” the centre said in its latest forecast.

Air quality in parts of Indonesia’s Kalimantan and Sumatra regions, where the fires are concentrated, was at dangerous or very unhealthy levels as of Tuesday, government data show. Malaysia has also suffered, with choking haze in late August prompting the government to move its leader’s annual National Day speech to an indoor venue. A state of emergency was declared for part of Sarawak state earlier this month.

A hotspot is defined as a location where satellites detect an elevated surface temperature, indicating a potential fire. The dryness has impacted Indonesia’s vast natural resources sector, with water supplies dwindling at a major nickel complex and palm oil production expected to take a hit.

Slash-and-burn methods used to clear farmland have previously been linked to the fires, and dry undergrowth can also ignite carbon-rich peatland, which can smolder for long periods and be difficult to extinguish.

Smoke plumes from fires in Kalimantan drifted toward Singapore because of a shift in winds, alongside smoke haze from Sumatra, the National Environment Agency said on Monday. The agency expects the haze to persist over the next 24 hours, with air quality ranging from high-moderate to mid-unhealthy conditions.

There may be a slight uptick in rainfall in parts of Sumatra and Kalimantan next week, which could temporarily ease fire risks, according to Takahisa Nishikawa, senior decision support meteorologist at Atmospheric G2. “This may provide some relief, although it does not yet look like a widespread or sustained wetting pattern, and forecast confidence is lower at that range,” he said.

The fires in Indonesia add to a bad year for wildfires globally, with parts of Europe and North America also reeling from recent blazes. The current El Nino has a 75% chance of becoming “a historic event,” surpassing all records dating back to 1950, the US Climate Prediction Center said last week.