SINGAPORE - The worsened haze that Singapore saw on Tuesday (Oct 13) is expected to persist throughout Wednesday (Oct 14), the National Environment Agency (NEA) said in an update on Tuesday evening.

The 24-hour Pollutant Standards Index (PSI) reading for the next 24 hours is expected to be in the low to mid sections of the unhealthy range. Visibility could also be reduced, particularly in the early morning.

The haze had deteriorated on Tuesday due to haze blown in from the surrounding regions, as the 24-hour reading moved entirely into the unhealthy band.

As of 11pm, the 24-hour PSI was between 117 and 137. The three-hour PSI, not tied to a health advisory, stood at 105.

While a multinational task force helping Indonesia put out the forest fires in South Sumatra has met with some success, an extended dry spell has complicated matters.

It could take about 10 days before the flames could be largely extinguished, said Indonesian Coordinating Minister for Political, Legal and Security Affairs Luhut Pandjaitan.

News also emerged that the list of corporate suspects that Indonesia is probing has grown to 12 firms, nine of whose bosses were questioned by police last month.

On the local front, another 20 firms have declared that their products are free of raw materials from companies alleged to be responsible for Indonesia's fires. This brings the total number that have signed the Singapore Environment Council's (SEC) form to 38.

The NEA has also taken action against a sixth firm, PT Bumi Andalas Permai, for possible transgressions of the Transboundary Haze Pollution Act.

For haze updates, visit the NEA website (www.nea.gov.sg), the haze microsite (www.haze.gov.sg), follow NEA on Facebook (www.facebook.com/NEASingapore) and NEA Twitter (@NEAsg), or download the myENV app.