Residents of Bangkok were able to enjoy a brief respite from the haze as cleaner air and blue skies returned to the city over the weekend after the hazardous ultra-fine PM2.5 dust particles -- which had amassed in the capital since the start of the month -- were blown away by the wind.

However, PM2.5 dust concentration levels remain at unhealthy levels in the North and Northeast where open agricultural burning has been reported, particularly in areas where there are sugarcane plantations, leading to PM2.5 permeating the air.

Nasa's Fire Information for Resource Management System, an open-source fire detection tool, was still showing thousands of fire hotspots in Thailand's agricultural areas over the past week. Hotspots have also been detected in parts of Cambodia, Laos and Myanmar where rice fields have been replaced by sugarcane plantations.

On Saturday afternoon, the Air Quality Index showed high levels of air pollution in many provinces. For example, in Khon Kaen, the average PM2.5 concentration was 63 microgrammes per cubic metre (µg/m³), 98 µg/m³ in Lampang, and 131 µg/m³ in Phrae. According to the World Health Organisation, the safety threshold is 25µg/m³.

The burning of sugarcane fields has contributed significantly to the rise of air pollution especially during the crop harvest season which spans from December to March. However, it's an issue that has hardly been dealt with by the government despite its hazardous impacts on the environment and people's health.

That is because sugarcanes feed the sugar industry, a major export sector. In 2018, Thailand exported over 11 million tonnes of sugar and earned 115 billion baht in revenue.

This might explain why the current and previous governments of Prime Minister Gen Prayut Chan-o-cha have favoured this industry.

This emerges clearly in the government's policy to promote increased production of sugarcane over the past five years. The former administration pushed for an amendment to a law that restricted the number of sugarcane-processing factories. With the amended law, there has been an increase in the number of sugarcane factories which have consequently brought about increased revenue from sugar and the by-products of sugarcane such as ethanol and biomass power.

The government has recognised large sugar producers, such as the Mitr Phol Group, as "state partners" in not only promoting technology and know-how to local farmers but also guaranteeing to buy sugarcane from them.

The state's support came during a hike in sugarcane prices three years ago. As a result, the total area of sugarcane plantations in Thailand increased from 9.5 million rai to 12 million rai between 2013 and 2019, according to the Office of Cane and Sugar Board.

By contrast, insufficient efforts have been made to prevent the burning of sugarcane fields. Each year, the government has let the provincial officials control burning activities in their localities despite their limited access to financial and human resources. The government has often blamed sugarcane farmers and farm labourers -- who set fires to their fields-- and asked them to reduce their sugarcane cutting workloads for quick cash.

But the sugar industry is more complex and it is hard to blame just one actor. Let me explain this through the voices of a farmer and a labourer whom I had conversations with and we will see why pollution will never go away if the government does not change the way it supports the sugar industry.

FARMER: "With orders of higher volumes for sugarcanes and the government supporting the sugar industry, sugarcane millers asked me to extend sugarcane plantations. And I did. But I ended up in debt. So now I can't leave this industry because I must pay off my debt."

In this case, the miller gave the farmer a number of sugarcane harvesters and trucks so the latter could catch up with the need for a faster pace of harvesting. But those items were not free.

They were given as a 60-million-baht debt on the part of the farmer. So the farmer needs to extend the area of his plantations to a total of over 3,000 rai by way of both renting and buying farmland from others.

It's the only way he can increase his sugarcane production to earn more income to pay off the debt in instalments. With debt, he also can't quit and must commit to delivering sugarcanes to the miller.

Some of his farmer friends decided to set fires on their plantations, instead of using harvesters, so they can cut cost and spare some money to pay for their debt.

LABOURER: "I did not want to burn the plantations. Who wants to do it? Burning makes sugarcane lose its weight and sweetness, reducing its sale value. But I did. I must meet the target set by my employer or they will find somebody else to replace me."

What do their stories tell us? Farmers and labourers, who are on the bottom rung of the sugar industry, are forced to carry the burden of fast-pace production, so the miller can keep up with increasing domestic and global demand for sugar.

Burning of fields will remain an unavoidable consequence as long as the government keeps sugar production as its top priority.

Instead, the top priorities for the sugar industry should be measures to prevent open-burning, provide debt relief for farmers, ensure fairer wages for labourers, and explore ways to diversify economic crops.

For now, industry and the government need to cut down their appetite for sugar revenue.

Paritta Wangkiat is a Bangkok Post columnist.