Aerial footage shows the thick clouds of air pollution blanketing parts of Thailand as the country closed hundreds of schools today (February 26).
Levels of the harmful PM 2.5 particles in the atmosphere have soared in recent days sparking health warnings.
Video from Trat province in the east of the country shows the toxic smog blanketing rural areas.
It hangs in the atmosphere due to low pressure, lack of winds and dry conditions then moves over cities.
Wildfires on mountains in the region that have been burning for seven days have also added to the levels of pollution.
Government officials and independent environmentalists have blamed a combination of the weather conditions, crop fires, pollution from industrial developments and soaring numbers of cars on the roads.
The Bangkok Metropolitan Administration closed public schools from today because of the excessive air pollution.
They said that most of the smoke and haze was blowing in from Cambodia with light easterly winds.
Levels of PM2.5 particles in the atmosphere have passed 100 microns per cubic metre for the previous two days.
The harmful pieces of dust can become trapped in the body leading to illness and lung problems. Bangkok Municipality spokesman Pongsakorn Kwanmuang said all Bangkok public schools were ordered to close until Friday.
The Thai government has been criticised for its handling of the country's air pollution crisis.
Measures introduced last year to reduce pollution included spraying water into the air to increase humidity, which helps to absorb particles of pollution.
''Unfortunately, this mitigation does not appear to be effective, since the volume of water is minuscule compared to actual rain,'' wrote data scientist engineer Worasom Kundhikanjana.