Air quality: Mumbai ranks well below average in air quality, due mainly to the city’s legacy manufacturing base, especially foundry production, combined with high volumes of car traffic. Mumbai has the highest level of average daily nitrogen dioxide emissions in the Index, at 86 micrograms per cubic metre. Similarly average daily levels of suspended particulate matter, at 202 micrograms per cubic metre, are almost twice the Index average. Sulphur dioxide levels are also high, at 34 micrograms per cubic metre, compared to the average of 23 micrograms. Mumbai has recognised the challenge and has implemented an air quality code, and monitors air quality at different locations around the city with the results published on a web site. However it is marked down for not monitoring carbon monoxide emissions. Mumbai is also one of two cities in the Index that do not inform citizens about air pollution and its associated health dangers