Chiang Mai was declared a "disaster zone" earlier this month when thick smog engulfed the region.

"We hope to relieve the worry of Chiang Mai residents and boost tourism in the run up to Songkran Festival," Wichai said.

The festival will begin on April 13.

Wichai said he had already written to the Social Development and Human Security Ministry to inform it of his decision to remove the "disaster zone" label.

According to Wichai, the "disaster zone" label has allowed him to assist people financially. "But so far, we haven't needed the disbursement at this point," Wichai said.

The haze problem hit the country's North early this month, affecting the health of local people.

As of Friday, the situation had returned to normal in all provinces except Mae Hong Son, where dust particles smaller than 10 micrograms in size (PM10) in the air stood at 150 micrograms per cubic metre.

The normal level requires that PM dust particles are no more than 120 micrograms per cubic metre.

Six aircraft are continuing to carry out royal rainmaking operations every day to clear up the haze, reduce air pollution and to tackle the drought.

According to the Public Health Ministry, the air pollution has increased the number of patients seeking treatment at stateowned medical facilities.

Between March 15 and March 22, 57,765 patients sought treatment in Chiang Mai, Lamphun, Lampang, Mae Hong Son, Phayao, Chiang Rai, Phrae, Nan and Kanchanaburi  or about 7,220 patients a day on average. Of them, more than 90 per cent had respiratory problems.

"With the situation improving, the number of patients in these provinces has already come down to just 4,605 on average on Thursday," Public Health Minister Mongkol na Songkhla said.

The Nation