A kindergarten in Chatuchak district has suspended classes because of air pollution that has landed Bangkok on the top 10 list of worst-polluted cities.
With an "unhealthy" reading of 157 on the Air Quality Index at 10.26am on Wednesday, Bangkok still lagged far behind the Afghani capital Kabul (at 576), Delhi in India (306) and Mongolia's Ulaanbaatar (300), Greenpeace Thailand noted on Twitter, but no one is cheering it up the rankings.
Surang Khamneungnet, director of Jananan Kindergarten in Chatuchak, said pupils had been kept indoors in recent days and the grounds sprayed with water three times a day, but the children had become listless and were eating less.
The school was due to close on Wednesday for the National Teachers Day but will remain closed on Thursday and Friday because of the air pollution, she said.
Northern Chatuchak district has for days seen unsafe levels of PM2.5 - airborne particles 2.5 micrometres in diameter or smaller.
The safe limit is 50 micrograms per cubic metre of air. In Chatuchak it rose to 71 on Wednesday, down from 95 on Tuesday.
Chulalongkorn University logistics expert Manoj Lohatepanont at a seminar on Tuesday advised schools to consider closing temporarily to reduce health risks for students and curb the number of cars on the roads, one source of PM2.5.
Prime Minister Prayut Chan-o-cha separately said the Education Ministry should use its discretion in deciding whether "at-risk" schools should be closed.