Dark days for residents of the capital as local air pollution gets thick ahead of Tết.

The Saigon Times reports that on Thursday, January 21, a number of flights to and from Hanoi had to be diverted or delayed due to poor visibility related to extreme air pollution.

Vietnam Airlines had to reroute a flight from Saigon to Hai Phong, while two others on the same route were sent to Da Nang instead of Hanoi, while three others from different parts of Vietnam ended up landing elsewhere.

Pacific Airlines had to move flights around as well, and both carriers saw their schedules for the day disrupted by these changes. 

The flight issues were blamed on low cloud cover and dense smog. Hanoi has been experiencing high AQI level throughout the last week, and on Thursday evening the monitoring app AirVisual ranked the capital first on its major cities ranking with a reading of 335, firmly in the "hazardous" zone.

City officials have blamed the problem on industrial activity, construction, vehicle emissions and uncollected garbage related to a strike by sanitation workers. Winter weather patterns are also exacerbating the issue, while Prime Minister Nguyễn Xuân Phúc has tasked relevant ministries and state agencies with monitoring factory and emissions and cracking down on heavily polluting facilities.

[Photo via La Gazzetta Aeroportuale]