BANGKOK: Southeast Asian cities were among five most polluted in the world on Friday according to air-monitoring organization IQAir, with Ho Chi Minh City ranked second-most polluted, followed by Phnom Penh and Bangkok fourth and fifth, respectively.In the Thai capital, a thick smog was seen covering the city’s skyline. Workers, especially those who spend most of their time outdoors, were suffering.“My nose is constantly congested. I have to blow my nose all the time,” said motorcycle taxi driver Supot Sitthisiri, 55.