At 9 am on January 27, a monitoring station operated by the Ministry of Agriculture and Environment on Giai Phong Street recorded an air quality index (AQI) of 200, classified as very unhealthy.
At the same time, the station in Long Bien Ward reported an AQI of 163, while the site on Khuat Duy Tien Street recorded 155, both at unhealthy levels.
IQAir ranked Hanoi as the world’s third most polluted city on the morning of January 27, with an AQI of 221, behind Delhi in India at 312 and Cairo in Egypt at 252. Several monitoring points across the capital reached very unhealthy or hazardous levels, including Tay Ho at 329, Cau Giay at 216, Thanh Xuan at 221, Ha Dong at 210 and Hai Ba Trung at 212.
Air pollution began to intensify again from January 25 as calm winds and temperature inversion caused fine dust to accumulate near the ground. The AQI reflects air quality and its impact on human health, with higher values indicating greater health risks. Authorities said current pollution is mainly driven by PM2.5 fine particulate matter.
Beyond Hanoi, the Department of Environment said air quality in several northern localities also ranged from unhealthy to very unhealthy, including Bac Ninh at 206, Haiphong at 202, Hung Yen at 189 and Thai Nguyen at 182.
The agency forecast that air pollution in northern Vietnam would worsen on January 28. Hanoi, Hung Yen and Ninh Binh could remain at very unhealthy levels, while Haiphong, Quang Ninh, Bac Ninh and Thanh Hoa are expected to experience unhealthy air quality.
