Fog blankets much of the country including Dhaka, what the met office says
The density of fog in the capital Dhaka had eased considerably over the past two days, with sunshine returning. However, since morning today, Friday the capital has once again been enveloped in fog.
According to the Bangladesh Meteorological Department (BMD), the same situation is prevailing across about two-thirds of the country, including Dhaka.
The extent of the cold wave has, however, decreased compared to yesterday. A cold wave is affecting seven districts today, down from 16 districts on Thursday.
After at least four consecutive days, Dhaka saw sunshine on Wednesday, and fog began to lift in other parts of the country as well. Yesterday, although the usual winter fog was present, there was sunshine from early morning.
Speaking to Prothom Alo on Friday morning, meteorologist Shahanaz Sultana said fog is spread across at least two-thirds of the country today, including the capital. Fog is present in most areas except parts of the Rajshahi, Rangpur and Khulna divisions.
Fog had persisted for almost the entire final week of December and cleared on Wednesday. The question is why, after two relatively fog-free days, dense fog has suddenly returned today.
Meteorologist Bazlur Rashid told Prothom Alo that fog is normal during winter, but its unusual intensity may be due to the absence of a western low-pressure. Typically, such a low-pressure arrives about twice a month, but none has been observed since December.
When there is a low-pressure, it brings rain, which helps reduce fog, and also increases wind speed, allowing fog to disperse, added the meteorologist.
In addition to the absence of a westerly low-pressure and low wind speeds, air pollution is also a contributing factor to the fog, Bazlur Rashid said. When the air is filled with extremely fine dust particles, fog tends to remain dense. He believes air pollution is therefore one of the reasons behind the persistent fog.
Alike yesterday, Dhaka’s air has been unhealthy since early morning today. This morning, the Air Quality Index (AQI) stood at 155. Although it was 177 Thursday morning, it rose to 277 at night, indicating that pollution levels increased from evening through the night. The main pollutant is fine particulate matter, or PM 2.5.
Bazlur Rashid added that fog has already begun to ease in various places in the Rajshahi, Rangpur and Khulna divisions. Fog persists in parts of the Dhaka, Barishal and Chattogram divisions, but it may gradually lift as the day progresses.
Meteorologist Shahanaz Sultana said there is some chance of sunshine returning to the capital after midday.