For the first time, American space agency NASA unveiled a global interactive map indicating the levels of nitrogen dioxide in the air. The regions and cities with the most gas levels in the air stood out in bright red.

NASA scientists used high-resolution global satellite images that indicated air quality. The comprehensive global map traced air pollution trends in the last 10 years and covered 195 cities.

A blue rating indicated the least polluted. The grading system sweeps to green, yellow, orange and all the way to red, which showed the regions and cities with the highest levels of nitrogen dioxide.

NASA unveiled two types of nitrogen dioxide data. The first type included absolute gas concentrations. The second type covered gas trends in the last 10 years. High levels of nitrogen dioxide covered the top cities in highly developed and developing countries.

Majority of lands in North America and Europe showed a middle green to yellow nitrogen dioxide air levels, excluding the highly populated New York area. 

UK's midlands, southeast and north of England glowed bright red. Most areas in Germany, the entire Netherlands, Belgium, Paris, northern-most Italy, Russia's Moscow and Poland's Warsaw also received a red rating.

China, South Korea and some regions in Japan showed high levels of nitrogen dioxide in the air. All of Australia and most of the southern hemisphere showed very low levels of the gas.

South America's major cities, although a small part of the landmass, glowed red as well as the South African region surrounding Pretoria and Johannesburg.

"These changes in air quality patterns aren't random. When governments step in and say we're going to build something here or we're going to regulate this pollutant, you see the impact in the data," said NASA's atmospheric scientist Bryan Duncan from Maryland-based Goddard Space Flight Center.

Duncan's team used the Dutch-Finnish Ozone Monitoring Instrument to track the air pollution trends from 2005 all the way to 2014. The instrument detects the yellow-brown nitrogen dioxide, which are commonly emitted by power plants, industrial factories and cars.

NASA's team also compared the satellite recordings to the countries' emission regulations, urban growth rate and national gross domestic product.

The interactive air quality map was published in NASA website.