The city suffers from severe air pollution, 80% of it due to cars. The remaining 20% is due to industrial pollution. Other estimates suggest that motorcycles alone account for 30% of air and 50% of noise pollution in Tehran. Tehran is also considered one of the strongest sources of greenhouse gas emissions in the Middle East. Enhanced concentration of carbon dioxide over the city (that are likely originated from the anthropogenic urban sources in the city) is easily detectable from satellite observations throughout the year.