NASA recently released long-term time series of NO2 pollution over global cities. The data sets were retrieved using observations from Ozone Monitoring Instruments onboard AURA satellite. Among other features of NO2, an interesting pattern is visible in terms of NO2 pollution levels in various cities in the United States and India. In recent years, Indian cities have been in the news for very bad particulate matter air quality, therefore, it is interesting to see that NO2 pollution level in many Indian cities is many folds lower than US cities.
The following figure shows 10 year mean of NO2 pollution level over selected US and Indian cities. Interestingly, New York city and Los Angels NO2 levels are almost 3 times higher than Delhi, whereas it is about 9 times higher than Pune. But, it is also true that NO2 trends in Indian cities are increasing whereas US has reduced its NO2 level in many cities over last one decade. These interesting feature of different types of pollution also tell something about development stage of each country. All the data reported here are taken from NASA website.