Hanoi’s Air Turns Hazardous as AQI Levels Spike Across the Region
Hanoi woke up on Sunday to a thick layer of hazardous pollution, with air quality plunging into the "very unhealthy" category across the capital and much of northern Vietnam — marking the first major smog event of the 2025–2026 winter season.
By 7 a.m., AQI levels at the monitoring station outside Hanoi University of Science and Technology had surged from 150 the previous night to 210, a level associated with significant health risks. Several other monitoring points also recorded alarming spikes: Nguyen Van Cu reached 197, Khuat Duy Tien Park hit 160, and neighborhoods such as Thanh Xuan, Le Duan, Tay Ho and Vinh Tuy saw AQI values between 223 and 282 on the IQAir network.
Poor air quality extended well beyond the capital. Hung Yen’s Thang Long 2 Industrial Park reported an AQI of 170; Bac Giang reached 154; Hai Duong and Phu Ly measured 153; and Thai Binh Bridge recorded 189.
The situation was made worse when Hanoi’s official air-quality portal went offline on Sunday morning due to an expired domain, leaving residents unable to access local real-time data. For several hours, global aggregator IQAir ranked Hanoi as the fifth most polluted city in the world, comparable to Delhi, Kolkata, Tashkent and Baghdad.
In response, the Ministry of Agriculture and Environment ordered immediate cross-sector actions to reduce emissions. Thermal power plants, steel mills, chemical factories and fertilizer producers were instructed to operate emissions-control systems at maximum capacity, scale back production when AQI rises above 200, and absolutely avoid releasing untreated exhaust. Construction sites must cover work areas, clean vehicle wheels, spray water to limit dust, or suspend dust-generating activities during high-pollution periods.
Traffic police were directed to intensify checks on trucks carrying uncovered materials and older vehicles emitting thick exhaust fumes. Health agencies advised vulnerable groups — including children, seniors, and people with respiratory conditions — to minimize outdoor exposure. Schools were told to restrict outdoor activities whenever pollution reaches unhealthy levels.
Authorities also announced plans to use satellites, drones and digital monitoring tools to identify abnormal emission sources, promising to publicly disclose violations as Hanoi prepares for more stagnant and polluted winter air in the coming days.