Haze from fires in Indonesia blanketing Singapore could persist for weeks or longer, Prime Minister Lee Hsien Loong said on Thursday, as the smoke drove air quality to "hazardous" levels and disrupted business and travel in the region.

 

Illegal burning of forests and other land on Indonesia's Sumatra Island to clear space for palm oil plantations is a chronic problem during the June to September dry season.

 

One Indonesian minister accused Singaporeans of acting like children, but pollution levels in the normally pristine city-state have shattered records set in 1997, raising diplomatic tensions and concerns about the economic impact.

 

On the fourth day of heavy smog, the smell of burned wood filled the air, skyscrapers were barely visible and haze hung in the tunnels that link Singapore's metro stations and shopping malls in the central core. Some residents wore surgical masks or covered their faces with handkerchiefs when they walked outside.

 

Singapore will suffer "an immediate hit to tourism", investment bank Barclays Plc said, noting that retailers, hotels, restaurants, gaming and other tourism-related sectors make up about 5-6 percent of the city-state's economy.

 

Singapore, which usually enjoys clear skies, saw its air quality deteriorate sharply on Monday. Its pollution standards index soared to a record of 371 at 1 p.m. on Thursday and then swung between the "very unhealthy" and "hazardous" levels.

 

The pollution readings in Singapore have exceeded the peak of 226 hit in 1997 when smog from Indonesian fires disrupted shipping and air travel across Southeast Asia.