Air quality in the city-state was in the "very unhealthy" range as of that afternoon, Bloomberg reported, citing data from Swiss monitor IQAir. Kuala Lumpur, which had earlier topped the list, ranked second.

IQAir's live ranking compares more than 100 major cities and is updated hourly. By the afternoon of Oct. 8, Kuala Lumpur had returned to the top with a reading of 221, while Singapore had dropped to sixth at 166, a level the monitor classes as unhealthy.

The spike comes days before Singapore's annual Formula One race weekend.

Singapore's National Environment Agency put air quality at unhealthy levels in all five regions of the island. The 24-hour Pollutant Standards Index ranged from 101 to 132 at 1 p.m. on Oct. 7, according to AsiaOne.

The agency said in its latest outlook that dry conditions are forecast over most of southern Southeast Asia for the next few days, keeping the risk of fires and transboundary haze elevated.

Across the border, Johor Regent Tunku Ismail Sultan Ibrahim ordered all schools in the state to close on Oct. 8 and 9 as a precaution, The Star reported, citing state education and information committee chairman Muhammad Naqib Md Ghazali.

The Singapore Flyer and commercial buildings are shrouded in haze at the Marina Bay area in Singapore, Sept. 15, 2026. Photo by Reuters

The closure affects 617,258 students at 1,198 schools, according to Malay Mail.

Muhammad Naqib urged parents to limit their children's outdoor activities and seek medical attention if they develop a cough, sore throat or breathing difficulties. He also asked employers to offer flexible arrangements to working parents.

Batu Pahat, a Johor district about 140 km northwest of Singapore, was the worst hit. About 200 schools, kindergartens and nurseries there had already been ordered shut, according to The Star.

The district's Air Pollutant Index reached 208, a level Malaysia classes as very unhealthy, before easing to 197 on the morning of Oct. 7, Malay Mail reported.

By 9 a.m. on Oct. 8, 38 of Malaysia's 68 air quality monitoring stations were recording unhealthy readings, including all eight in Johor, the outlet said, citing Department of Environment data.

Haze from fires on the Indonesian islands of Sumatra and Borneo has hung over Kuala Lumpur and Singapore for more than a month, AFP reported on Sept. 30. Hot, dry conditions linked to the El Nino weather pattern have fueled the fires, which are also tied to land clearing.

Malaysia's meteorological department expects an inter-monsoon period beginning Oct. 9 to bring thunderstorms and heavy rain that could ease the haze, according to Malay Mail.