Hanoi (VNA) - Authoritiesin Thailand’s capital city of Bangkok ordered nearly 450 schools to close onJanuary 22 as pollution reached dangerously unhealthy levels.
Bangkok, the world's most visited city, sawlevels of PM 2.5 particles at 78.3 pg/m3. A level above 35 is consideredunhealthy by the World Health Organisation (WHO).
PM 2.5 particles can include dust, soot and smokeand are so small they can lodge deep in the lungs and enter the bloodstream.
Bangkok's air quality index (AQI) on January 22 was163, according to data from AirVisual. Anything above 150 is consideredunhealthy.
Like many growing Asian cities, Bangkok isplagued by vehicle fumes, dust from construction sites and emissions fromindustry but the burning of stubble and undergrowth in fields in surroundingrural areas is believed to contribute to much higher pollution levels in thedry, winter months.
Last January, the city closed schools for a weekbecause of pollution./.