This looks worse than air pollution in Chinese and Indian cities.
Photograph below is from December 2019:
"Amid crippling US-led sanctions on Iran and a continually weakened currency, enterprising young Iranians are taking advantage of the country's cheap electricity to mine Bitcoin,
however, it's coming at a huge cost to fellow citizens as the immense power-sucking process of mining the crypto-currency has contributed to a national electricity shortage and rolling blackouts.
... major cities across Iran have over the past month been observed covered in a blanket of smog, which many worry could be toxic, given reports that desperate power plant operators have been resorting to burning low-grade fuel oils to generate electricity.
While third-world countries with socialist systems offering free electricity like Venezuela have recently been in the news due to the rise of crypto-mining on the cheap, this is the first instance of illegal mining occurring on such a level as to contribute to major power outages.
... the Islamic Republic ... has some of the cheapest electricity in the world.
The combination of the pandemic, US sanctions, and government mishandling of the health crisis has set off "an economic depression that could be worse than any in Iran’s modern history," according to one analyst's assessment.
"The strains on the electricity grid led the government to start cracking down on illegal mining operations, and about 6,000 mining machines were recently confiscated in Markazi province, the managing director of the Markazi Electricity Supply Co., told ISNA," Bloomberg details.
... Some outspoken advocates pushing for greater global adoption of crypto-currency as a prime medium of exchange have said precisely that it could be used by governments to beat sanctions.
Venezuela, Iran, or even Russia could one day be the first test cases for such as scenario as their economies continue to be severely strained by US punitive economic measures."