Updated Feb 13, 2021 | 20:20 IST According to the data, the primary source of SOx in these areas is the brick manufacturing industry. The primary source of NOx (nitrogen oxides) pollutants is also the brick manufacturing industry. NGT directs action against illegal brick kilns in Rajasthan [Representative image] | Photo Credit: iStock Images New Delhi: The National Green Tribunal on Saturday directed immediate action against illegal and unauthorised operational brick kilns in Shri Ganganagar city of Rajasthan while hearing a plea stating that a huge quantity of toxic elements from brick kilns cause serious health hazards in the region. The plea stated that the brick kilns emit toxic fumes containing suspended particulate matters rich in carbon particles and high concentration of carbon monoxides and oxides of sulphur (SOx) that are harmful to eye, lungs and throat. These air pollutants also stunt the mental and physical growth of children.