The government and opposition parties are locked in a war of words over the worsening microdust situation with the crisis now expected to last until Friday.
The argument started with opposition leader Natthaphong Ruengpanyawut posting a sarcastic message on his Facebook urging Prime Minister Paetongtarn Shinawatra to give Thais a chance to breathe fresh air before going to Switzerland in pursuit of more opportunities for the country.
"While the PM is breathing in deeply the fresh air in Davos, Switzerland, and trying to attract more investors to Thailand in the hope of making this year a year of opportunities for the country, millions of Thais are inhaling extremely polluted air here into their lungs," said Mr Natthaphong, also leader of the opposition People's Party (PP).
The PM is in Davos-Klosters, Switzerland for the annual World Economic Forum (WEF).
Mr Natthaphong also questioned Ms Paetongtarn's ability to ensure the government curbs PM2.5 pollution, saying the government's promise to offer sugar cane farmers an incentive if they agree to avoid burning sugar cane leaves when harvesting had yet to make its way to cabinet.
As a result, many farmers had already opted for the cheaper means of harvesting their sugar cane -- burning their leaves first, said Mr Natthaphong.
The government's attempt to ban burned sugar cane from being sold to sugar factories won't help either, as many farmers had already conducted burning and added more pollution to the air, he said.
"Let me call on the PM and cabinet to take this problem more seriously. The PM in particular had better stop dodging this problem," he said.
The government should have communicated more clearly to sugar farmers about the incentive for them to harvest their products without burning their leaves long before the harvest season, he said.
Even parts of Bangkok are being affected by air pollution caused by biomass burning in the agriculture sector, which is actually easy to detect by using satellite images of hotspots, he said.
"They [the government] have all the equipment and resources to do so while lacking clarity as to how they want these tools to be used," he said.
"Before [the PM] goes to find more opportunities, maybe all we need is a clear and practical action plan [from the government," he said.
Responding to Mr Natthaphong's remarks, government spokesman Jirayu Houngsub said he couldn't believe the amount of sarcasm coming from the opposition leader.
Mr Natthaphong was well aware the PM was representing Thailand at the overseas conference, meeting world businessmen and encouraging them to invest in Thailand, said Mr Jirayu.
"Maybe Mr Natthaphong might want to learn what a good opposition leader is like. He might want to learn how to behave like a gentleman in politics," said Mr Jirayu.
As of 10am Wednesday, 103 schools in Bangkok had suspended onsite classes and switched to online learning, due to the PM2.5 pollution crisis, which is forecast to last until Friday, said Bangkok governor Chadchart Sittipunt. It was originally expected to last just two days.
All 50 districts of Bangkok on Wednesday had a serious air quality problem, with five in a critical situation, said AirBKK, City Hall's air quality monitoring agency.
The governor blamed the situation on poor air ventilation in the capital which was coupled with high traffic emissions resulting from factors such as more congestion on inner Bangkok roads where flyovers are now closed as part of the Orange Line electric train project.
The Bangkok Metropolitan Administration on Thursday will begin banning trucks which have not registered for permission to enter Bangkok's low-emission zones.
A total of 259 security cameras equipped with AI technology will be used to keep an eye out for trucks flouting the ban. Those who flout it face the prospect of legal action.