Bangkok schools closed over 'unhealthy' pollution levels

Smog Bangkok Image copyright AFP/Getty Image
Image caption The smog is among the worst Thailand has ever seen

Toxic smog in Bangkok has forced more than 400 schools to close for the rest of the week, to protect children from its harmful effects.

Thailand's capital city is experiencing some of its worst-ever air pollution levels, caused by ultra-fine dust particles known as PM2.5.

Traffic exhaust, construction works, burning crops and pollution from factories are blamed for the haze.

Authorities' efforts to clear the air have so far failed.

Image copyright AFP/Getty Images
Image caption Specialist respirator masks to filter the particles have quickly sold out

The government has tried seeding rain clouds, reducing traffic, and hosing down streets, with little impact.

Those celebrating the Lunar New Year holidays next week have been asked not to burn incense or light fireworks.

Image copyright AFP/Getty Images
Image caption The smog has smothered the city for the past few weeks
Image copyright AFP/Getty Images
Image caption Dust particles can cause inflammation of the lungs

According to The World Air Quality Index project (AQICN), Bangkok's Air Quality Index (AQI) is currently at around 170, making it "unhealthy".

But that still doesn't match New Delhi, which is currently hovering around 390, a "hazardous" level of pollution.

Image copyright European Photopress Agency
Image caption Bangkok residents have been urged not to use cars

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