Air pollution smothered Bangkok today (Jan 16) reaching almost SIX TIMES the levels considered dangerous to humans.

The level of harmful PM 2.5 particles in the air reached 275 on the IQAir monitor when the safe level is just 50.

Scientists say the smog is caused by a combination of agricultural burning of waste crops to clear land ready for the next planting season - a process known as 'slash and burn - and mild weather with a lack of wind and rain.

Smogs worst between January and March when farmers burn crops and there is a winter low-pressure system in which cold air is trapped closer to the ground by warm air above - preventing the pollution from being dispersed naturally.

The Thai government has been criticized for its handling of the country's air pollution crisis - failing to tackle the problem for three consecutive years.

Data scientist engineer Worasom Kundhikanjana said measures such as spraying water into the air were ineffective.

She said: 'Unfortunately, this mitigation does not appear to be effective, since the volume of water is minuscule compared to actual rain.'