HANOI, Vietnam — Thick smog blanketed Hanoi on Friday, obscuring buildings and leaving nine million residents choking on toxic air as the Vietnamese capital topped a list of the world's most polluted major cities.
Authorities urged people to wear masks and limit time outdoors, but commuters told Agence France-Presse they were struggling to breathe through the putrid smog, now a fixture of the winter months in the city.