Air pollution clouds Bangkok as 'dust dome' forms over city

Footage shows the thick haze covering roads and buildings, with the Air Quality Index reading 194 for the level of harmful PM2.5 particles in the air.

Environmental minister Varawut Silpa-archa said low atmospheric pressure and high-rise buildings had trapped dust and other pollutants from farm fires, which had caused a 'dust dome'.

The minister said he has had ordered provincial governors to ask farmers in their area to avoid burning waste crops - a process known as 'slash and burn' that farmers use to clear their land.

Smog is at its worst in Thailand 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 criticised for its handling of the country's air pollution crisis - failing to tackle the problem for three consecutive years.