Heavy air pollution has forced Iranian authorities to close government offices and declare a two-day public holiday in the capital, Tehran.

It's the second time in a month that offices are closed over air pollution. State television says a government committee has decided that pollution levels warranted the closure of all government offices, as well as schools and industries on Wednesday and Thursday because of "polluted and unhealthy" conditions.

Critics say each holiday incurs about $130 million in financial losses.

Iran occasionally announces holidays and traffic restrictions over pollution. Health experts say many Iranians suffer from pollution-related ailments.