At 6:30 p.m., the city’s Air Quality Index (AQI) rose to 231 – a level classified as “very unhealthy” - surpassing Delhi and Lahore (India). Several central wards reported even higher readings, including parts of West Lake and Giai Phong Street, where AQI levels reached 295 earlier in the evening.

The surge was driven mainly by PM2.5, microscopic particles that can penetrate deep into the lungs and bloodstream. Concentrations peaked 174 µg/m³, a level that can trigger immediate health effects, especially among children, the elderly and people with respiratory diseases.

Many residents reported eye irritation and throat discomfort as visibility dropped and buildings disappeared behind thick haze.

Meteorologists attributed the spike to dry, cold weather conditions combined with temperature inversion and low wind speeds, trapping pollutants close to the ground.

Hanoi has appeared regularly in the global top 10 most polluted cities over the past week. City authorities recently issued urgent directives, warning residents to limit outdoor activity in the early morning and evening and to use protective masks capable of filtering fine particles.

Construction sites are now required to improve dust control and install artificial intelligence-based monitoring cameras, while illegal waste and crop-burning will be strictly penalised.

Hanoi also plans to pilot mist-spraying systems in residential areas, major roads and parks to help reduce airborne dust levels.

Hanoi orders urgent measures to control air pollution

VOV.VN - Hanoi has issued an official directive ordering urgent measures to curb air pollution across the city, signed by Vice Chairman of the municipal People’s Committee Nguyen Manh Quyen.