As of December 8, Hanoi experiences very high air pollution levels reaching the “purple” zone - the emergency health warning level, particularly hazardous for children and the elderly. With AQI readings reaching up to 239, PM2.5 concentrations are estimated to fall within the 150–200 µg/m³ range.
Based on the 2024 PM2.5 data, VnExpress estimates that Hanoi residents are passively exposed to air pollution equivalent to smoking two cigarettes a day, with an average PM2.5 level of 41 µg/m³.
Air pollution peaks both day and night
Hanoi is entering its third wave of air pollution since the beginning of the season, starting from November 28According to the Hanoi Air Quality Forecasting and Early Warning System.
On dry and cold days when temperature inversion occurs, air pollution is often very poor during the night and early morning, but improves around midday and in the afternoon.
However, in early December, the air pollution has worsened, persisting throughout both day and night, commonly remaining at hazardous levels, thereby increasing the duration of its impact on public health. Air quality is commonly recorded at between 100 and 250 AQI, ranging from “Poor” to “Very Poor” levels, which pose direct health risks to children and the elderly.
The AQI indicates the concentration of PM2.5 - ultrafine particles which are 30 times smaller than human hair, can penetrate deep into the human body and bloodstream and cause detrimental effects to lung, cardiovascular or overall health.
According to the World Health Organization, PM2.5 is a “silent killer.” World Bank data from 2021 show that 40% of Hanoi’s population (approximately 3.5 million people) are exposed to PM2.5 concentrations above 45 µg/m³, which is five times higher than the WHO guideline.
Deaths linked to PM2.5-related causes in Hanoi account for 32% of the national total, equivalent to around 5,800 fatalities.
7th most air-polluted city in the world
Hanoi ranked in the top 10 most air-polluted cities in the world, according to the IQAir report in 2024.
From 2018 to 2024, Hanoi has been one of the few major cities in Southeast Asia where PM2.5 levels have been continuously rising, compared to neighbouring cities like Bangkok, Kuala Lumpur, and Singapore, where air pollution has shown either stabilization or gradual improvement
With an average PM2.5 level of around 45 µg/m³,Hanoi’s pollution is lower than major hotspots such as New Delhi but still far exceeding WHO guidelines. After 25 years since the first PM2.5 studies were conducted in Vietnam, the city’s PM2.5 levels remain at around 30–40 µg/m³.
Experts noted that Hanoi’s deteriorating air quality comes from the rapid growth of private vehicles, uncontrolled construction dust, seasonal open burning of waste and agricultural by-products, as well as pollution transported from neighboring industrial zones.
The city’s dense urban structure and unfavorable winter meteorological conditions further trap pollutants near ground level, intensifying smog episodes.
Toward 2045: National Action Plan to target air pollution
Amid escalating air pollution, Prime Minister Pham Minh Chinh has approved Decision No. 2530/QD-TTg on November 19, 2025, on the National Action Plan for Air Pollution Control and Air Quality Management for the 2026–2030 period, with a vision toward 2045.
The plan sets a target that by 2030, Hanoi will have at least 80% of days in a year expected to record “Good” or “Moderate” air quality levels under the VN_AQI index. The annual average PM2.5 concentration will fall below 40 µg/m³, a 20% reduction compared with the 2024 average as measured at national air quality monitoring stations.
Previously, Hanoi established Low-Emission Zones - where fossil fuel-powered motorbikes will be banned to reduce the emissions from vehicles in the respective area, with ambitions to improve the air quality.
However, the Ministry of Agriculture and Environment pointed out that emissions from transportation account for only 38%, while the other major contributors to air pollution are construction (29%) and open waste burning (15–16%).
Thereby, the National Plan has focused on reducing emissions from these two big factors. It requires construction sites to install and operate emission-treatment systems; construction activities to comply with regulations on shielding, watering, and proper transportation methods to minimize dust. It also requires rural areas and craft villages to significantly reduce open waste burning as well as organize recycling, and relocate facilities causing serious pollution.
Besides that, the plan focuses on nine key groups of solutions, including policy improvements, control of industrial emission sources, promotion of green transport, and enhancing air quality control ability, alongside the establishment of a National Steering Committee.
