Jakarta – A choking and dangerous haze that has been blanketing the Indonesian city of Pontianak in the early morning has caused delays in flight arrivals and departures, officials said yesterday.

An airport official at the city in West Kalimantan, said one landing was delayed yesterday and about six flights were delayed over the weekend.

Visibility over Pontianak was a mere 50 m early in the morning but improved drastically later due to strong winds, said the meteorology office.

On Friday, health officials handed out up to 1,000 smog masks to drivers. Many residents have been complaining of sore eyes and respiratory problems, the state Antara news agency said.

The meteorology office said it had not rained in the area for at least a week and the thick haze had occurred daily in the early hours. It added that the smoke came from the use of fire to clear land around the city.

Environmentalists have said although the haze lasts only a few hours a day, it has high levels of dust and other particles which are dangerous to health.

Indonesia has banned land clearing by fire since 1999 following widespread forest and ground blazes in 1997-98 that sent haze over large parts of South-east Asia – causing serious traffic and health hazards.

But fire remains the easiest and most cost-efficient way of clearing land, and Indonesia's millions of small farmers cannot afford more expensive clearing ways.

Such economic considerations weigh on the minds of officials who enforce clean-air laws and crack down on fire-starters.