Firefighters flew over a forest to dump extinguishers over a raging wildfire in Thailand.

Helicopters from the Ministry of Natural Resources and Environment and Department of Disaster Prevention and Mitigation were dispatched as the fire spread throughout the Ob Luang National Park in Chiang Mai province on February 27.

Authorities said the aircraft made 39 total flights and dumped around 19,500 litres of water on the burning forest.

More than 250 personnel have been deployed to tackle the 142 'hot spots' detected in Chiang Mai.

The fires caused PM2.5 fine dust levels to rise to 87 and 77 microgrammes per cubic metre in the province's Fang and Chai Prakan districts respectively.

Despite continuous firefighting efforts, the flames reignited in the evening due to hot and dry conditions.

Chiang Mai governor Nirat Phongsittithaworn has visited the national park's firefighting command centre to oversee the operations and boost morale.

Dangerous levels of deadly PM 2.5 particles are recorded every year in Thailand between December and April.

Despite paying lip service for several years, politicians have failed to stop individuals from burning their land due to it being cheaper and easier than modern farming methods.

In March 2023, the Public Health Ministry of Thailand reported that around 1.3 million people in the country had been unwell due to the rising levels of air pollution. Officials said 200,000 residents were hospitalised in a single week.

They warned hospitals in December 2023 to prepare for an influx of patients.

It came as researchers from Peking University in Beijing, China, also discovered that long-term exposure to particulate matter PM.25 air pollution is associated with an increased risk of lung cancer.

In December, Dr Krittai Thanasombatkul from Chiang Mai, Thailand, died of lung cancer. He had previously blamed PM 2.5 microdust particles for his condition.

The New York State Department of Health say PM 2.5 increases the risk of heart disease, asthma, and low birth weight.

While medics from South Korea published research in the National Institute of Health in the United States that said the pollutant increases the risk of stroke, ischemic heart disease, chronic obstructive pulmonary disease (COPD), lung cancer, and other illnesses such as immune deficiency and even obesity.