( CNN ) -- Iran has declared a two-day public holiday in Tehran after air pollution hit dangerous levels . All schools , public offices , universities and banks in the Iranian capital will be closed Wednesday and Thursday , the Islamic Republic New Agency reported . Tehran 's downtown skyline was barely visible Tuesday . Residents have been asked to avoid outdoor activities and encouraged to use public transportation . Health warnings have been issued informing people suffering from lung and heart conditions to stay at home , as well as the elderly and children , according to Iran 's Ministry of Health 's website . Police officers , taxi drivers and other workers who are forced to work outside are required to wear surgical masks while on the job , the ministry said . This is the second time in less than a week Iran has declared a public holiday due to extreme pollution . Tehran shut down last Wednesday to cut down on emissions and traffic . The government says despite a 40 percent drop in traffic since the last holiday , the pollution has reached critical levels . CNN meteorologist Mari Ramos says conditions could worsen due to a combination of dry air , low wind and lack of rain . Iran has fought pollution for decades , specifically in the sprawling Tehran metropolis which is home to an estimated 12 million people . The city already implements traffic plans that require a special permit to drive though downtown Tehran . Cars must also alternate driving days , depending on their license plate numbers . According to research by Tehran 's municipal government , over 80 percent of the pollution is caused by some 4 million cars operating throughout the capital , state-run Press TV reported . `` In our long-term plans to solve the pollution problem , we will get rid of old and dilapidated autos , standardize our auto manufacturing , upgrade the quality of our fuel and our mass transit system , '' Mohammad-Javad Mohammadizadeh , head of Iran 's Environmental Protection Agency said , the semi-official Mashregh news reported Monday . Mohammadizadeh also said the government is considering artificially creating rain and wind . About 2,500 people in Tehran die every year because of health problems caused by pollution , Iran 's Environmental Protection Agency has said . CNN 's Shirzad Borzorgmehr contributed to this report .
Tehran 's schools , public offices , universities and banks close Wednesday and Thursday . Tehran shut down last Wednesday to cut down on auto emissions and traffic . The government says despite a 40 percent drop in traffic , pollution is at critical levels .