Hanoi is facing with the air pollution (photo by Nguyen Hue)
With this air quality index level, people are advised to avoid outdoor activities, keep windows closed to prevent exposure to polluted air, wear masks when going outside, and use air purifiers indoors.
The AQI is a scale ranging from 0 to 500, with higher values indicating greater pollution levels and health risks. AQI readings above 300 are considered hazardous, while a range of 0-50 signifies good air quality.
According to the National Centre for Hydro-Meteorological Forecasting, the northern region of Vietnam will face another strong cold spell on February 22-24.
Hanoi will continue to experience light rain and mist until this weekend, with the lowest temperature of 15-18 degrees centigrade.