Schools have been allowed to suspend classes as cancer-causing air pollution worsens in Bangkok, Thailand.

The Bangkok Metropolitan Administration (BMA) has granted authority to headteachers and district chiefs to suspend classes for up to 15 days when levels of PM 2.5 - the toxic pollutant caused by illegal crop burning - breach the unsafe threshold.

BMA spokesman Ekwaranyu Amrapan said on January 31 that schools must 'modify teaching methods' and suspend outdoor activities when the PM2.5 reading exceeds 37.5 microgrammes per cubic metre for three consecutive days.

Local media reported that the governor of Bangkok can order indefinite school closures if the PM 2.5 exceeds 75 microgrammes per cubic metre for three days.

The safe level set by the World Health Organisation (WHO) is five microgrammes per cubic metre, figures routinely ignored by ineffective officials in Thailand, which relies on cheap agricultural burning to meet food demands.

Dangerous levels of deadly PM 2.5 particles are recorded every year in Thailand between December and April - sparking concern from residents with hundreds of thousands also admitted to hospital with respiratory ailments.

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.