Sugarcane farmers, often targeted as a major source of PM2.5 pollution, have significantly reduced field burning practices to comply with government regulatory measures. Despite the consequences they have suffered - higher costs, labour shortages, increased operational risks, and volatile cane prices - governmental support measures have been underwhelming.

Earlier this year, the Ministry of Industry ordered the closure of the Thai Udonthani Sugar Mill and its associated power plant for processing too much burnt sugarcane.  At 43.11% of the total, its throughput constituted the highest proportion in the country.  Government policy dictates that mills use no more than 25% burnt cane, the rest being fresh, but the closure left many farmers with few options: large quantities of cane were left unprocessed for days, deteriorating in quality and price. The disruption extended beyond burnt cane, with trucks carrying fresh cane also stuck queuing at the mill.

The government regularly sets ambitious goals to promote the harvesting of fresh cane. Beside the recent closure, it also approved a system for reducing payments to farmers who deal in burnt cane, starting at 30 baht per ton, and rising to as much as 130 baht if burnt cane exceeds 25% of their total harvest. While the aim is to eliminate what many believe is a major source of PM2.5 pollution, sugarcane farmers contend that banning the purchase of burnt cane does not address the root cause of the problem.    

“They say that the PM2.5 was there before sugarcane harvesting, that PM2.5 readings are high before sugarcane cutting, high before the mills open, and high even after the mills close their vaults,” said Danuphon Sontang, a sugarcane farmer in Chum Phae district, Khon Kaen province,

PM2.5 pollution comes from many sources -motor vehicle and factory emissions - but in recent years, agricultural burning has become an increasingly significant contributor. This includes the burning of rice straw, cornfields, and fields used for rotational farming, as well as sugarcane burning in Thailand and neighboring countries.

According to Kasikorn Research Center, the sugarcane harvesting process accounts for about 23% of agricultural particulate emissions and produces an average of 2.4 million tons of greenhouse gases per year, a tradeoff for the more than 100 billion baht it generates in annual income.

Burning in sugarcane fields is more intense than rice straw burning. Rice plants generally grow no taller than 150 cm, while fully matured sugarcane reaches 2–3 metres. Sugarcane leaves are also highly flammable. Once a fire starts, flames can surge up the full height of the cane, producing far more smoke and particulate emissions than other crops.

Sugarcane growers running family farms in Chum Phae, Khon Kaen admit that they used to regularly burn their fields. The reason, they say, was a shortage of labor and high wages, coupled with the fact that their cane fields were planted in narrow rows that could not accommodate harvesting machinery.

Early-season sugarcane is planted before the rainy season and harvested around February–March. Late-season cane is planted from October to November and harvested in the same period the following year. Cane burning typically begins in November and continues for 3–4 months until March or April.

Cane burning can be divided into two stages: burning before harvest and burning after the cane has been sent to the mill. Air-pollution concerns generally arise from the first stage, which produces large amounts of particulates. The ash generated, often referred as “black snow”, is not confined to the burning area. Instead, it can drift across large areas, affecting air quality and public health.

With the issue now under public scrutiny, sugarcane farmers are often harshly criticised for being selfish, uneducated, and irresponsible, despite the fact that many have significantly reduced burning in recent years to comply with government measures, receiving little support in return.

“Villagers understand the problem, but do people in the cities or the government?” asked Sophit Ingsa, a sugarcane grower in Nam Phong District, Khon Kaen. Maybe not; often left from the discuss of how best to discourage sugarcane burning is any consideration of farmers’ rising production costs and thin profit margins.

Sophit Ingsa, a sugarcane grower in Nam Phong District, Khon Kaen

How profitable is sugarcane?

As Danuphon explains it, a rai of sugarcane typically yields around 10–20 tons of harvested cane. Production costs average about 10,000 baht per rai and if yields fall below 10 tons a rai, farmers incur losses. With good management, sugarcane can be planted once and harvested over several regrowth cycles, though this depends heavily on soil quality and requires an additional 3,000 baht per rai investment each year.

Danuphon is one of approximately 427,000 registered sugarcane farmers in Thailand. One of the world’s major sugar exporters, Thailand ranks behind just Brazil and India. Around 70% of the country’s sugar production is exported, generating more than 100 billion baht in revenue. Under the former junta leader Gen. Prayut Chan-o-cha, the sugar industry received strong state backing. His government set an ambitious target to turn Thailand into ASEAN’s Bio Hub by 2027, a policy direction that remains in place. The plan was to increase sugarcane production for purposes of bioenergy and bioplastics.

In 2024–2025, Thailand sugarcane cultivation totaled around 11 million rai. The country’s poor Northeast accounted for the largest share at roughly five million rai.  The number of sugar mills in the country also expanded rapidly, reaching 58 nationwide. All of this was in keeping with Thailand’s 2015–2026 Cane and Sugar Strategy, which sought to have the total cultivation area expand to 16 million rai and further increase the number of mills by 2026.

Despite government support and strong global demand, life as a sugarcane farmer remains challenging, even though farmers’ interests are theoretically protected under the Cane and Sugar Act. As noted by Chaiwat Khamkaenkhun, President of the Nam Phong Sugarcane Farmers Association in Khon Kaen, the Act establishes provisions for farmers’ representatives and related organisations to speak on their behalf.

Chaiwat Khamkaenkhun, President of the Nam Phong Sugarcane Farmers Association in Khon Kaen

There is a limit to what can be done, however.  Assoc Prof Dr Khwantri Saengprachatanarug of the Department of Agricultural Engineering, Faculty of Engineering, Khon Kaen University, notes that while the Act stipulates revenue sharing between farmers and mills, it does not provide farmers with extra compensation for value added during processing.

Assoc Prof Dr Kwantri Saengprachatanarak of the Department of Agricultural Engineering, 

Faculty of Engineering, Khon Kaen University.]

Purchase prices at sugar mills also fluctuate from year to year. In the 2024–2025 production season, the price was set at 1,160 baht per ton, low compared to the previous year’s 1,420 baht per ton, which many farmers regarded as the break-even level. There are predictions that prices may fall below 1,000 baht per ton next season. If that happens, sugarcane farmers will face even greater hardship, particularly as they are expected to reduce burning practices, an adjustment that carries additional costs.

Why burn?

The first reason is labour. With burnt cane, harvesters can cut several stalks at a time because there are no leaves to strip.  This allows them to harvest a large number of stalks in a short period. In contrast, fresh cane must be cut stalk by stalk and, as the leaves are longer and tougher, labour costs are higher.  When cutting fresh cane, workers can harvest about 1.8 tonnes per day, compared with up to 5 tonnes per day when the cane is burnt.

These days, labour is in short supply.  According to sugarcane grower Sophit, the physically demanding nature of the work does not appeal to younger workers, leaving most cutters aged between 40 and 70.

The height of fresh sugar cane compared with that of a cane cutter

Time is also a critical factor. Sugar mills operate steam-powered systems that require a steady supply of cane to avoid losses, forcing mills to set fixed opening and closing dates. Each mill sets their schedule differently. If they estimate that cane supplies will be low, they close early. Normally they close around March but may extend operations into April.

The machinery is not designed to process cane with leaves attached and farmers are responsible for removing leaves before delivering cane to the mill. Under a tight schedule, they have only narrow windows to sell their cane. As a result, many see burning as the most practical option.

Burning sugarcane has long been a traditional farming practice, predating public concern over PM2.5. For most farmers, mechanical harvesting is not cost-effective. Harvesters cost 10-12 million baht. They also require large plots with row spacing of at least 1.85 metres, while the average sugarcane area per household is only 15.6 rai, according to the Kasikorn Research Center.

According to ‘Net’, a 60-year-old sugarcane field worker in Khon Kaen, burning is sometimes absolutely necessary. Thick piles of cane leaves covering the ground makes it impossible for workers to spot wild elephants that descend from the mountains in search of food and burning before harvesting allows workers to avoid accidents.

When workers harvest fresh cane, massive piles of cut leaves also make it difficult to walk. A single rai of sugarcane (10–15 tonnes) produces around 1.5–2.5 tonnes of leaves. If workers aren’t careful, they can easily be cut by the leaves’ sharp edges. More importantly, farmers have no effective way to manage the large quantity of waste. Cane leaves are slow to decompose and in the absence of rain, remain on the ground for four to five months.

If farmers replant, they can plough leaves back into the soil. But if they want a regrowth crop, the leaves must be removed early.  Otherwise, decomposition can trigger accidental fires that damage the crop later on. Discarded cigarette butts can also start fires that spread across entire fields and “if fields burn, farmers might not be able to sell,” said association president Chaiwat.

Many farmers resort to controlled burning, despite its drawbacks. The process requires many workers and carries serious risks, as reflected in annual reports of fatal accidents. Mills also deduct payment for burnt cane because of its lower sugar content and weight. Depending on daily cane volumes and mill capacity, trucks can be stuck in queues for six to seven days, during which the cane lose value or may even begin to rot.

Despite higher costs, farmers are complying with government efforts to address the PM2.5 crisis. In Chum Phae and Nam Phong districts, major sugarcane-growing areas, burnt fields are now rarely seen along the roadsides. The association president and many farmers agree that burning has decreased significantly.

A decade ago, more than 60% of processed sugarcane was burnt. By 2019, that share had fallen below 50%, and over the past three to four years it declined further to around 30%. With tighter government measures and farmers’ compliance, the reduction has been consistent.

Proportion of burnt sugarcane to the total cane delivered to the mill over the past ten years

A part of this is the result of government policy.  Initially, mills were instructed to accept no more than 20% burnt cane. In 2024, the Ministry of Industry set a season target to reduce the proportion of burnt cane by more than 10% from the previous year, a goal was successfully met.

For the 2024–2025 production season, Office of the Cane and Sugar Board (OCSB) data as of April 8 shows that only 13 million tonnes of burnt cane entered factories out of a total 92 million tonnes—just 14%, the lowest proportion ever recorded. The decline is also reflected in hotspot data. Between 6 December 2024 and 8 May 2025, Thailand recorded 68,114 hotspots nationwide. Of these, only 4,436, or about 7%, were located in sugarcane plantations.

Underwhelming support

Apart from prohibitive measures, the government has a support scheme that provides 120 baht per tonne for farmers who harvest fresh cane. The measure has been in place since the 2020-21 production season, but only registered farmers who hold a quota with a sugar mill are eligible for payment.

The president of the Nam Phong Sugarcane Farmers Association added that farmers can only receive this support if the entire tonne of cane delivered is fresh. A single burnt stalk can leave a farmer ineligible.

Despite meeting strict requirements, farmers still won’t necessarily get what was promised by the government. Payments have not been consistent. Since the 2023-24 season, sugarcane growers have been left waiting while sugarcane associations nationwide continue to push and follow up with the authorities.

According to the Nam Phong Sugarcane Farmers Association, while the 120 baht per tonne does not significantly boost profits, it does help farmers reduce losses. Costs ultimately depend on each grower’s own management practices. The payment encourages farmers to keep harvesting fresh cane.

In June, the Cabinet approved a new support measure of more than 5.175 billion baht for farmers who deliver fresh cane in the 2024-25 season—equivalent to 69 baht per tonne.  While this sounds promising on paper, farmers still have not received answers regarding outstanding payments from the previous two years.

“I wish the government sector would prioritise PM2.5 measures that do something beyond punishing sugarcane farmers.  People who deserve sympathy are being punished.  Think of how much hardship they endure before selling each stalk of cane,” association president Chaiwat said.