Visible dense haze engulfed Hanoi throughout January 14 with the air quality index (AQI) monitored at most sensor station reaching unhealthy levels from 151 to 193 from early in the morning.
Thai Prime Minister Prayut Chan-o-cha on September 30 held an urgent video-conference with leaders of 16 provinces and related ministries after PM2.5 air pollution exceeded the safe level in Bangkok and surrounding provinces.
The capital of Hanoi was named as the most polluted city in the world on September 26, with the southern largest economic hub of Ho Chi Minh City not far behind.