Iran’s Air Pollution Emergency: Toxic Winter Skies, Widespread Closures, and the Compounding Pressures of Drought and Water Crisis

Iran is facing one of its most dangerous air pollution episodes in recent years, as toxic smog spreads across major cities.

Iran is facing one of its most dangerous air pollution episodes in recent years, as toxic smog spreads across major cities including Tehran, Isfahan, Karaj, Ahvaz, Mashhad, Tabriz, Arak, and others—triggering mass school closures, remote work directives, and escalating health risks for millions. The pollution, driven by atmospheric stagnation, industrial emissions, vehicle exhaust, dust storms, and the seasonal surge in mazut burning, is unfolding at a moment when the country is already grappling with prolonged drought, declining rainfall, and chronic water shortages that further weaken environmental resilience.

According to Sadegh Ziaeyan, head of Iran’s National Weather Forecasting Center, from December 21 to 24 (1–4 Azar), Iran’s large and industrialized cities will face steady atmospheric stability, causing a dangerous rise in pollutant concentrations. This official warning coincided with sweeping announcements by provincial authorities: all kindergartens and preschools across Tehran Province (except Firouzkouh) will remain closed from Saturday to Wednesday, traffic restrictions have tightened, and the daily traffic permit system has been suspended. The odd-even license plate rule limiting which cars can leave their homes in the city is now enforced, and vulnerable groups—including people with respiratory or cardiac conditions, pregnant women, and parents with young children—have been urged to work remotely.

In parallel, Khuzestan Province announced that schools and universities in Ahvaz, Karun, Hamidiyeh, and Shushtar will operate online due to severe pollution. East Azerbaijan declared schools in Tabriz, Oskoo, and Bonab non-attendance for Saturday and Sunday. Similar closures rolled out in Qazvin, Zanjan, West Azerbaijan, Isfahan, Yazd, Alborz, and Khorasan Razavi—where the education ministry cited both pollution and a spike in respiratory illnesses such as influenza. These simultaneous shutdowns reflect the national scale of the environmental emergency.

Tehran’s AQI reached 140 yesterday and is expected to climb as high as 160, placing the capital in a “red” category that is dangerous for all groups. On Monday, November 24, Tehran’s Air Quality Index officially entered the “hazardous” range for the entire population, prompting the crisis headquarters to enforce expanded closures: all kindergartens, preschools, special-needs centers, schools, and universities will function remotely; private and public employees may work from home; and businesses must close by 8:30 PM. Heavy trucks are banned from entering the city until the end of the week, and compliance is monitored by police and CCTV cameras.

In other regions, similar emergency directives have been issued. Isfahan, Tabriz, Karaj, Ahvaz, and Mashhad are all under orange-level pollution alerts, while many cities are preparing for multi-day disruptions. The Meteorological Organization reports no meaningful rainfall until at least Wednesday, exacerbating pollution buildup. Shahr-e Kord reached –9°C, while Bandar Abbas recorded 32°C, illustrating how Iran’s climate extremes can worsen smog dynamics.

These acute pollution events are occurring against a background of extraordinary health and human losses. According to Iran’s Deputy Minister of Health, air pollution caused nearly 59,000 deaths in 2024 (1403), equivalent to 161 deaths per day or seven deaths per hour, with economic damage estimated at $17.2 billion, or 47 million dollars per day. The ministry’s National Air Pollution Report notes that pollutants such as PM2.5, PM10, ozone, carbon monoxide, nitrogen dioxide, and sulfur dioxide reached levels far beyond WHO guidelines in most metropolitan centers. Last year, Tehran, Isfahan, Karaj, Mashhad, Ahvaz, Tabriz, Arak, Kermanshah, Qom, and Yazd all recorded hundreds of days exceeding the WHO’s 24-hour PM2.5 limit of 15 µg/m³, with some districts—such as Ramhormoz, Behbahan, Hendijan, and parts of southern Tehran—reaching 4 to 9 times the WHO limit.

One of the major structural drivers of Iran’s winter smog is massive mazut burning. On November 13, mazut consumption in Iranian power plants exceeded 21 million liters per day, enough to fill a 14-kilometer line of tanker trucks. Iran traditionally relies on natural gas for energy, but winter demand spikes force power plants to burn mazut—one of the dirtiest fuels in the world—producing dense particulate emissions that quickly blanket valleys and industrial corridors. Last winter, Iran set a record for mazut consumption due to severe gas shortages. The administration of President Masoud Pezeshkian attempted to limit mazut use but ultimately could not risk widespread blackouts, leaving environmental regulations sidelined.

These atmospheric crises are further aggravated by Iran’s intensifying drought and water scarcity, especially in Tehran. Severely reduced rainfall over the last decade has left the capital’s reservoirs—Latian, Lar, Mamloo, and Taleghan—dangerously low. Low rainfall means no atmospheric cleansing, causing pollutants to remain suspended for longer and accumulate in the urban canopy. At the same time, reduced hydropower output forces greater reliance on thermal power plants, which in turn burn mazut, reinforcing the pollution cycle. Dry soils, desiccated wetlands, and parched farmlands across Iran generate enormous dust emissions, contributing to particulate pollution in cities hundreds of kilometers away.

Other structural contributors—aging vehicle fleets, millions of carbureted motorcycles, deteriorating public transport systems, outdated refineries, and uncontrolled industrial emissions—compound the crisis. In cities such as Ahvaz and Karaj, the combination of industrial output and dust storms creates persistent pollution layers. In Isfahan, the drying of the Zayandeh Rud has created new dust sources. In Tehran, topographic inversion traps pollutants under a dome of stagnant cold air.

Iran’s environmental emergency is no longer confined to seasonal smog—it is part of a multi-system breakdown driven by climate change, water scarcity, outdated infrastructure, and acute energy shortages. Toxic winter air is only the most visible symptom of deeper structural vulnerabilities that threaten public health, economic productivity, and long-term urban sustainability.

With air pollution now causing tens of thousands of deaths annually, billions in economic losses, nationwide school closures, and unprecedented disruptions to daily life, Iran faces an escalating crisis that requires structural, long-term solutions: cleaner energy sources, strict anti-mazut policies, modernized public transport, refinery upgrades, strengthened environmental governance, and climate-resilient water management. Unless decisive action is taken, Iran’s winter skies will remain toxic—and the country’s intertwined air, water, and climate crises will continue to deepen.