Air pollution in the Thai capital forced more than 350 schools to close on Friday, city authorities said, the highest number in five years.Bangkok officials also announced free public transport for a week in a bid to reduce traffic in a city notorious for noxious exhaust fumes.

Air pollution has led to the closure of over 350 schools in Bangkok, as the city ranked seventh in the world for pollution. Levels of harmful PM2.5 pollutants were significantly above WHO guidelines.

The Bangkok Metropolitan Administration urged people to work from home for the rest of the week if they can, with air pollution forecast to worsen after already forcing the temporary closure of more than a dozen schools.

A mix of stagnant cold air, smoke from crop burning, and car fumes causes air quality to reach unhealthy levels.