Jakarta: Forest fires were still raging across Indonesia yesterday, with visibility cut to as low as 30 metres in parts of Borneo island, forcing cars to use headlights and throwing air travel into chaos.

The fires concentrated on the islands of Borneo and Sumatra are a regular occurrence in the dry season but appear to have worsened this year with more fires on highly flammable peatland and amid a hot spell ahead of the start of rains due this month.

Thick haze blowing across from Sumatra prompted Singapore to post a health advisory on Saturday, warning people to scale back vigorous outdoor activity.

The situation was slightly better yesterday, with Singapore's three-hour average Pollutant Standards Index (PSI) down as low as 27, after hitting a nine-year high of 150 on Saturday, the National Environment Agency's website (www.nea.gov.sg) showed.

A spokeswoman at the agency said that south-southeasterly winds had blown some of the haze away from Singapore, but warned that it could only be a temporary shift.