Hanoi continues to choke in ‘very unhealthy’ air as smog blankets northern Vietnam
Northern Vietnam woke up to a thick, unmoving blanket of smog on Dec. 9, with air quality in Hanoi and nearby Hung Yen Province plunging into « very unhealthy » territory for hours.
By 7 a.m., the monitoring station at Hanoi University of Science and Technology was showing an AQI of 204, a level that can affect even healthy individuals, while Hung Yen’s Thai Binh Ward surged to 246.
Other hotspots across the capital, including Tay Ho, Tran Vu and Hoang Quoc Viet, also slid deep into the red zone.
IQAir’s global index ranked Hanoi the world’s 9th most polluted city this morning, trailing only cities facing chronic haze such as Kolkata, which topped the list with 262.
Hanoi has been choking in heavy air pollution since late November. On Nov. 30, gIQAir briefly ranked it the world’s fifth most polluted city, comparable to Delhi, Kolkata, Tashkent and Baghdad.
The new spike is part of a longer pollution episode gripping the region from Dec. 8 to 14, driven by weak winds, temperature inversion and a lack of air circulation that traps dust, smoke, and industrial emissions close to the ground. Scientists expect the smog to peak around Dec. 11–12 before easing as a stronger cold front arrives to disperse pollutants.
But until then, authorities warn that several localities, including Hung Yen, Ninh Binh and Hai Phong, may continue to experience « very unhealthy » air, while Hanoi, Bac Ninh, Lang Son, Quang Ninh, Thanh Hoa, Nghe An, Ha Tinh and Phu Tho remain firmly in the « unhealthy » range.
Government agencies have activated emergency-response protocols as the haze thickens. Industrial plants, from thermal power stations to steel, chemical and fertilizer factories, have been ordered to strictly operate their emissions-control systems and curb production whenever AQI readings climb above 200.
Construction sites must boost dust-control measures, install shielding, enforce wheel-washing, spray mist and even pause high-dust activities when pollution spikes. Traffic police are cracking down on uncovered material trucks, over-aged vehicles spewing black exhaust and illegal trash burning, all major contributors to PM2.5 pollution during stagnant weather.
Health authorities are urging residents, especially children, the elderly, pregnant women and those with respiratory or heart conditions, to minimize outdoor exposure and use certified masks. Schools across the region have been instructed to restrict outdoor sports and activities when AQI readings hit unhealthy levels, as the smog wave is expected to linger for several more days.
By Gia Chinh – VnExpress.net – December 8, 2025