Tehran Grapples with 'Very Unhealthy' Air Pollution, Leading to Widespread Closures and Health Warnings

Crisis Grips Iranian Capital and Major Cities

Tehran, the capital of the Islamic Republic of Iran, has been plunged into a severe air pollution crisis, with air quality indices repeatedly reaching 'very unhealthy' and even 'extremely hazardous' levels in late November and early December 2025. The Swiss air quality technology company IQAir ranked Tehran as the world's most polluted city on multiple occasions, including September 26, 2025, and again in late November. Air Quality Index (AQI) readings in parts of Tehran soared past 200, with specific monitoring stations like Qarchak reaching 219 and Fath Square recording 213. The Qahjavarestan area notably hit an 'extremely hazardous' 297.

The crisis extends beyond the capital, affecting numerous other major Iranian cities.

• Mashhad
• Isfahan
• Urmia
• Tabriz
• Qom
• Karaj
• Ahvaz

and several cities in Khuzestan province, including Abadan, Behbahan, and Khorramshahr, have also reported red or orange alert levels for air quality.

Widespread Disruptions and Health Advisories

In response to the alarming pollution levels, authorities have implemented extensive measures to mitigate the impact. Schools and universities across Tehran and other affected provinces have been closed, with education shifting to online platforms. Government offices, banks, and other businesses have operated with reduced staff or mandated remote work.

Transportation has also faced significant restrictions, including bans on truck travel and limitations on private car usage, such as odd/even license plate schemes. Furthermore, operations at sand and gravel mines, as well as cement factories, have been halted.

Public health advisories have urged residents to avoid unnecessary outdoor travel, limit time spent outdoors, and wear masks. Vulnerable populations, including the elderly, children, and individuals with respiratory or cardiac conditions, have been strongly advised to remain indoors.

Severe Health and Economic Toll

The air pollution crisis is exacting a heavy toll on public health and the economy. The head of Tehran's Emergency Medical Services reported that 31% of all EMS missions during the first eight days of Azar (late November 2025) were related to pollution-induced health problems, marking a 9% increase from the previous month. During this period, 357 deaths were potentially linked to air pollution.

The Ministry of Health estimates that 58,975 Iranians died in the Iranian calendar year 1403 (2024–2025) due to exposure to fine particulate pollution, equating to approximately 161 deaths per day. Hospitals have also reported a 15% rise in respiratory cases and a 3% increase in cardiac complications. The Health Ministry's broader estimate suggests nearly 59,000 Iranians die annually from pollution-related illnesses.

Economically, the crisis is devastating. Annual economic losses due to health crises are estimated to exceed $17 billion. Tehran alone is reported to lose between $3.3 to $3.7 billion annually due to the combined effects of pollution, traffic, and mental health issues.

Root Causes and Official Response

Multiple factors contribute to Tehran's chronic air pollution. A significant geographical factor is temperature inversion, where a layer of warm air traps pollutants close to the ground, a phenomenon exacerbated by Tehran's location near the Alborz mountain range.

Vehicular emissions are a primary culprit, accounting for an estimated 80% of the city's pollution. The prevalence of old and aging vehicles, coupled with low-quality gasoline (high sulfur content and the use of the MMT additive), and high fuel consumption, are major contributors. Motorcycles alone are believed to contribute 30% of air pollution. Industrial pollution from facilities on the city's outskirts also plays a role.

A critical factor, particularly during colder months, is the burning of Mazut, a heavy fuel oil, by power plants and industries due to natural gas shortages. Iran's domestically produced Mazut has a sulfur content of 3.5%, seven times higher than international marine fuel standards. The country faces an estimated daily gas deficit of 300 million cubic meters this winter, increasing reliance on this dirty fuel.

Officials have voiced grave concerns. Mohammad Jafar Qaempanah, a deputy to President Masud Pezeshkian, warned that 'air pollution will kill if it becomes any more than this.' Government spokesperson Fatemeh Mohajerani described the situation as 'indefensible,' stating that 'what citizens breathe in Iran's major cities today can in no way be called clean air.' The governor of Tehran conceded that the issue has 'moved beyond a manageable problem and has become a crisis.'

The ongoing environmental crisis is set against a backdrop of severe economic difficulties and international sanctions, further complicating efforts to implement long-term solutions for cleaner air.