On Friday, Singapore woke up to a deterioration in air quality overnight, as a thin cloak of haze hung over the city-state. The country's environment agency said that its 3-hour Pollution Standards Index hit the unhealthy level at 10am SIN.
Neighboring Malaysia had already been feeling the effects of the drifting smog since mid-August, local media reported.
The latest bout of pollution comes even as Indonesia steps up efforts against the 'slash-and-burn' technique of cutting down vegetation on a patch of land, then burning off the undergrowth to make space for new plantations.
The country has arrested 454 individuals in connection with forest fires so far this year, more than double the 196 arrests made in 2015, Reuters reported, citing police data released on Thursday.
The 'slash-and-burn' method is prevalent in Indonesia as it the easiest, fastest and most cost-effective way to clear land. According to the World Bank, about 35 percent of the Indonesian workforce is employed in agriculture, with palm oil and pulp-and-paper industries key contributors.