Hossein, a Tehrani businessman in his 40s, wrapped his face with a scarf as he ventured out to work yesterday braving a noxious stew of choking pollution that has engulfed the Iranian capital for several days.
"The wind has picked up a bit but the smog is still thick and unbearable," he said. "And there's no sign of the rain or snow that the weather forecasters have been promising us."
Nestling in a bowl flanked by the spectacular snow-covered Alborz mountains to its north, Tehran suffers a pollution crisis every winter when cold air and windless days trap fumes spewed out by 3.8 million cars and hundreds of ageing factories.
But many of Tehran's 8.8 million residents like Hossein say the situation has become worse since 2010 when Iran started producing its own low-quality petrol in response to US-led sanctions on petrol imports.
The smog has added to the misery of Tehranis who are already struggling with rampant inflation and high unemployment resulting from the sanctions aimed at curbing Iran's nuclear ambitions.
During a similar alert last month, Iran's former health minister, Marzieh Vahid Dastjerdi, even urged Tehranis to flee the sprawling capital.
Air pollution in Tehran has claimed 4,460 lives in a year-long period since March 2011, an Iranian health ministry official said on Sunday. Another candidly acknowledged that carcinogens in Iranian-made petrol are higher than in other major world cities.
Iranian state radio warned on Saturday - when schools, universities and government offices were shut because of the smog - that heading outdoors was tantamount to committing "suicide".
Hossein, who did not want his full name used, said: "I've been to a lot of big cities around the world and this ranks right at the top [for air pollution]."
A 2011 report by the World Health Organisation ranked Tehran as one of the most polluted cities in the world, ahead of Bangkok, Shanghai and Mexico City. Los Angeles, another car-clogged metropolis, is four times less toxic than Tehran.
The pollution crisis is a highly-charged political issue in Iran. Regime officials, loath to admit that sanctions imposed by the West are having any effect, insist that the sickly yellow haze has nothing to do with locally produced petrol.
Even so, some usually dutiful state-run Iranian media are holding the government to account. The Tehran Times pointed out yesterday that other major Iranian cities such as Isfahan, Mashhad and Ahvaz are also suffering from increased pollution, reinforcing the view of experts that "the low quality of gasoline and diesel fuel is responsible".
The daily also lambasted the government for refusing to release US$2 billion (Dh7.34bn) to expand the Tehran metro system.
Efforts to boost public transport, including establishing lanes for buses only, have barely dented the pollution problem because of the growing number of cars, many of which are old and inefficient.
Even new cars off the domestic production block are not fuel efficient, or equipped with catalytic converters, the Tehran Times said.
Most Iranians are well aware that the current pollution crisis predates western sanctions. For many, the substandard petrol at the pumps highlights the regime's failure to invest in Iran's rickety infrastructure during the profitable years before sanctions tightened their grip.
The Tehran Times said: "There is no strong determination on the part of officials to reduce air pollution, and the citizens will continue to pay the price for this negligence."