An aerial view from Chiang Mai city in northern Thailand shows unhealthy levels of air pollution.

On Wednesday, the concentration of PM2.5 pollutants ranged from 170 to 200 across the city.

Website AirVisual ranked the city as third most polluted in the world for air pollution on March 3.

The unhealthy pollution is expected to worsen during the dry season. The poor air quality is blamed on agricultural burning and vehicle emissions.

Chiang Mai in northern Thailand has amongst the world's worst air pollution,ranking number three on March 3. The city has recorded levels over 200 on the PM 2.5 air quality index, rated as very unhealthy . Over the past 48 hours the city's main sports stadium has recorded an AQI between 134 and 326. The WHO safe figure is 25. A PM 2.5 reading of 200 is classed as very unhealthy, 300 as hazardous.
Most of the city was almost invisible to me when I was filming.
The monitoring station statistics are from Chiang Mai University Climate Change Data Centre which posted at the time of my filming "The PM 2.5 situation in Chiang Mai City this morning was at a level that had a huge impact on health". Website AirVisual ranked the city as third most polluted in the world for air pollution on March 3.