Air pollution continues to plague Bangkok as the Thai capital experiences stagnant weather coupled with seasonal agricultural burning.

A blanket of thick smog hovered over the city, which saw an average of 50.1 micrograms per cubic metre of PM2.5 today, the Bangkok Metropolitan Administration reported.

The 'safe' level of PM2.5 in Thailand is 50 micrograms per cubic metre.

The administration blamed the poor air circulation on temperature inversion when layers of cold air become trapped under warm air, preventing upward movement and the dissipation of pollutants near the ground.

The agency forecasted air pollution levels in Bangkok to temporarily ease on February 25 to 26.

Northern Thai provinces like Chiang Mai are also grappling with unsafe air pollution readings.

Thai media reported that the air quality in Chiang Mai had slightly improved last week after rain had hit the province, but were still beyond the 'safe' threshold.

Continued agricultural burning and forest fires caused the fine dust levels to spike once again.

Scientists found that the smog is at its worst in the country when farmers burn waste crops to cheaply clear their land between late October and April. This is combined with high numbers of polluting cars on the road and large construction projects across the capital.

The seasonal lack of wind and rain, combined with a winter low-pressure system in which cold air is trapped closer to the ground by warm air above – prevent the pollution from being dispersed naturally.

The Thai government has been criticised for failing to tackle the country's air pollution crisis, with bizarre measures such as spraying water into the air and giant purifiers having no impact.

Data scientist engineer Worasom Kundhikanjana said: 'PM 2.5 pollution has a seasonal trend in Bangkok and the northern provinces, but has only recently received public attention. During this winter haze, the harmful particle pollution level is high throughout the day, including on weekends.

'Unfortunately, spraying water into the air does not appear to be effective, since the volume of water is minuscule compared to actual rain.

'With the start of the monsoon season, the weather in Bangkok will get better, and public attention on this issue will likely fade. However, without immediate policy measures, the problem will come back again next winter.'