Many buildings in HCM City are covered by dense fog on December 17.
The Southern Regional Hydrometeorological Station said the fog was mainly caused by sharply rising humidity, which has reached saturation levels of 100 per cent.
High humidity combined with early-morning fog is expected to last through the rest of the day and may continue into the morning of December 18, according to forecasts. The fog could significantly reduce visibility, prompting authorities to advise road users to slow down, use low-beam headlights and maintain safe distances.
In the following days, humidity levels are expected to gradually decline, with clearer conditions developing during daylight hours.
Air quality data from IQAir, updated at 9 am on December 17, showed PM2.5 concentrations in the former Thu Duc City area at 92.4 micrograms per cubic metre, about 18.5 times higher than the World Health Organisation’s annual guideline level.
With an AQI reading of 177, the city ranked 12th among the world’s most polluted major cities, according to global air quality monitoring data.
Authorities have advised residents to limit outdoor activities, wear protective masks when necessary and closely monitor air quality updates as conditions evolve.
