Pupils in face masks leave classes today as government bosses closed more than 500 schools amid a worsening pollution crisis in Bangkok.

The Thai capital has been shrouded in a thick cloud of toxic smog for more than two weeks with authorities taking increasingly desperate measures to contain the pollution.

Despite spraying tonnes of water across the city in a bid to disperse the smog, the PM 2.5 air-quality index (AQI) which measures the amount of deadly particles in the air has remained stubbornly high - way above the acceptable level of 50.

Government chiefs took the step today to close all 439 schools in Bangkok. Dozens of private schools followed as well as establishments in neighbouring provinces with hundreds of thousands of kids now staying off school until next week.

Officials will continue their efforts to battle the smog tomorrow by flying drones and spraying water from hosepipes on skyscrapers.

The PM2.5 dust particles are extremely small and they are fine enough to be absorbed in the human bloodstream through the lungs. This will cause chronic diseases such as asthma, cancer, heart disease and stroke in the long term if there is exposure to air pollution.

Health experts have warned that the pollution is a ''silent killer'' and that at current levels was extremely harmful to anyone stepping outside. They said the cost of treating people could run into ''millions of dollars''.

The pollution is mainly caused by soar numbers of cars on the road, an explosion in construction projects and farmers burning sugarcane husks.

Pupils in face masks leave classes today as government bosses closed more than 500 schools amid a worsening pollution crisis in Bangkok.

The Thai capital has been shrouded in a thick cloud of toxic smog for more than two weeks with authorties taking increasingly desperate measures to contain the pollution.

Despite spraying tonnes of water across the city in a bid to disperse the smog, thg PM 2.5 air-quality index (AQI) which measures the amount of deadly particles in the air has remained stubornly high - way above the acceptable level of 50.

Government chiefs took the step today to close all 439 schools in Bangkok. Dozens more private schools as well as establishments in neighbouring provinces also followed suit - with hundreds of thousands of kids now staying off school until next week.

Officials will continue their efforts to battle the smog tomorrow by flying drones and spraying water from hosepipes on sky scrapers.

The PM2.5 dust particles are extremely small and they are fine enough to be absorbed in the human bloodstream through the lungs. This will cause chronic diseases such as asthma, cancer, heart disease and stroke in the long term if there is exposure to air pollution,

Health experts have warned that the pollution is a ''silent killer'' and that at current levels was extremely harmful to anyone stepping outside. They said the cost of treating people could run into ''millions of dollars''.

It is caused by soar numbers of cars on the road, an explosion in construction projects and farmers burning sugarcane husks.