The pollution standards index peaked at 371 on Thursday, breaking previous records and well above hazardous levels, before falling to about 300.
The haze is the result of forest fires started by farmers clearing land on the Indonesian island of Sumatra.
The issue has sparked accusations between the two neighbours.
Dr Vivian Balakrishnan, Singapore’s Environment and Water Resources Minister, wrote on his Facebook wall that he would demand “definitive action” from Jakarta.
“No country or corporation has the right to pollute the air at the expense of Singaporeans’ health and wellbeing,” he said.
However, Indonesian Minister for People’s Welfare Agung Laksono said that Singapore was “behaving like a child”.
“This is not what the Indonesian nation wants, it is because of nature,” he said.
Environment officials from the two nations have been holding an emergency meeting in Jakarta, to discuss the issue.
Since the haze arrived, Singapore’s buildings have been obscured by the polluted air and the smell of burnt wood has permeated the city-state.
A PSI reading above 200 indicates “very unhealthy” air, while a PSI score above 300 is “hazardous”. Readings are being posted on the website of the National Environment Agency.
continue reading BBC News – Singapore smog from Indonesia fire ‘could last weeks’.