By Kayhan Life and Kayhan London Staff
A senior Iranian lawmaker has confirmed that one of the country’s most damaging environmental practices—the large-scale burning of mazut, a heavy, low-grade fuel oil rich in sulfur—is not a temporary emergency measure but a state policy, approved at the highest levels.
Abdolreza Sepahvand, second secretary of the Majles Energy Commission, said this week that the burning of mazut at power plants is conducted under direct authorization from the Supreme National Security Council, the country’s top decision-making body on national security matters. According to Sepahvand, a formal directive issued to the Ministry of Oil and the Ministry of Energy allows power plants to burn more than 45 million liters of mazut daily.
Mazut produced in Iran contains approximately 3.5 percent sulfur—nearly seven times the maximum permitted under international maritime fuel standards. Because it cannot be exported legally, the fuel is burned domestically, effectively shifting the environmental and public-health costs onto Iran’s population.
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Each winter, as household gas consumption increases, authorities divert limited supplies away from power generation, forcing thermal plants to switch to mazut and diesel, which are highly polluting.
The practice, which produces dense particulate matter and toxic emissions, has become a central cause of Iran’s annual air-pollution crisis during the autumn and winter months, when major cities are routinely blanketed in smog.
State-affiliated media have provided glimpses of the scale of the operation. On December 13, the Fars News Agency reported that the use of mazut had spread across the country, with daily consumption exceeding 21 million liters by mid-November.
Fars said moving such quantities requires tanker convoys up to 14 kilometers long and identified the Muftah, Salimi, and Shazand power plants as the largest users. Follow-up reports from Fars confirmed that at least 15 thermal power plants—including facilities in Tehran, Isfahan, Bandar Abbas, and Tabriz —were affected.
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The Iran Open Data Center, citing leaked Ministry of Oil data, reported that mazut consumption at thermal power plants increased by an average of 46 percent nationwide over the past year. In several provinces, the rise was dramatic: 543 percent in Bushehr, 172 percent in Zanjan, 157 percent in Kohgiluyeh and Boyer-Ahmad, and 82 percent in Tehran.
Sepahvand said that although diesel reserves doubled in 2025, persistent natural gas shortages at power plants prompted authorities to activate the SNSC authorization. He also admitted that the excessive use of mazut and coal damages turbines, and noted that several power plants were taken offline last year due to wear from these fuels.
Iran holds the world’s second-largest natural gas reserves. But the regime’s mismanagement, corruption, and chronic underinvestment have left the energy sector unable to meet domestic demand. The impact is devastating and has led to surges in respiratory and heart-related illnesses in big cities, prompting authorities to issue public health warnings and close schools.
In a rare public admission last summer, Saeed Tavakoli, chief executive of the National Iranian Gas Company, said that “all power plants across the country operated at full capacity using mazut last year.” Despite such acknowledgments, senior officials continue to downplay or deny the scope of the problem in public statements.
Tejarat News, an economic news outlet, has described the burning of mazut as a normalized policy failure. It blamed worsening pollution, rising mortality, and long-term damage to public health on the lack of a credible plan to transition to cleaner or renewable energy. The state described the burning of mazut as an emergency response to energy shortages. However, the practice has become a defining feature of Iran’s broader energy and governance crisis.
