The monitoring station also reported hazardous air quality in Nam Tu Liem district as of 7 a.m. on March 4.
Hanoi was covered in fog on the morning of March 4, with the air quality index (AQI) reaching a bad level.
Experts believe that the drizzly conditions on the night of March 3 resulted in a high moisture content in the air, leading to the formation of fog.
The combination of air pollution and fog can reduce visibility and negatively impact the health of individuals, especially those in vulnerable groups.
Pham Hung road is covered in dense fog and dust.
The fog envelops Keangnam Hanoi Landmark Tower, the tallest building in Hanoi.
Most drivers are wearing face masks due to the polluted air.
The fog reduces visibility for drivers, leading many to have their lights on while driving in and around the city.

A scene from Tran Duy Hung road at 8 a.m. on March 4.