He said that the deaths were caused by heart attacks brought on by the air pollution and that the smog was responsible for 80 percent of the fatal heart problems that month in Tehran, one of the world's most polluted cities.

"It is a very serious and lethal crisis, a collective suicide," he warned. "A real revolution is needed to resolve this problem."

The new figures showed a sharp rise in pollution-related deaths in Iran, where 9,900 people died of pollution in the previous Iranian year (March 2005 to March 2006).

Carbon monoxide from car exhausts is blamed for the majority of deaths by creating respiratory and cardiac problems in Tehran, which has 1.3 million ageing cars with poor fuel efficiency, spewing lethal gases into citizens' lungs.

Half of Iran's six million cars fail to meet global standards and burn twice as much petrol as a European car. With pump prices at a mere nine cents a liter With pump prices merely at nine cents a liter (41 cents per gallon), streets are crammed with cars, with terrible traffic jams in rush hours.

The pollution problem becomes particularly acute during winter when a lack of wind and the cold air means that great clouds of smog sit on the city for days on end.

The authorities regularly ask the elderly and children not to leave their homes when the pollution is at its peak in Tehran, a city of at least seven million people. They also shut down schools to protect the pupils.

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