Pontianak – Haze from forest and bush fires returned here on Thursday, forcing some residents to wear masks, head of West Kalimantan provincial metereology office Suwardi said on Thursday.

"The smoke reduced morning visibility around the West Kalimantan provincial capital of Pontianak to less than two kilometers," Suwardi told AFP, adding that it forced many motorcyclists and residents to don masks before venturing out.

Despite warnings from authorities, small-scale farmers living around the provincial capital continued burning scrub to clear land, Suwardi said.

The haze, an annual hazard for millions of Indonesians and sometimes their neighbors, is largely from fires started illegally to clear land for replanting.

In 1997, thick haze caused by forest fires in Indonesia blanketed parts of Southeast Asia for months, causing serious health problems and traffic hazards, and disrupting commercial flights. Using fire to clear land has been illegal since 1999 in Indonesia, but prosecutions of violators are rare.