Adverse air quality can kill many organisms including humans. Ozone pollution can cause respiratory disease , cardiovascular disease , throat inflammation, chest pain, and congestion . Water pollution causes approximately 14,000 deaths per day, mostly due to contamination of drinking water by untreated sewage in developing countries . An estimated 500 million Indians have no access to a proper toilet,   Over ten million people in India fell ill with waterborne illnesses in 2013, and 1,535 people died, most of them children.  Nearly 500 million Chinese lack access to safe drinking water.  A 2010 analysis estimated that million people died prematurely each year in China because of air pollution.  The WHO estimated in 2007 that air pollution causes half a million deaths per year in India.  Studies have estimated that the number of people killed annually in the United States could be over 50,000. 
They occur mainly in the form of sulphur dioxide. It is produced in large quantity during smelting of metallic ores and burning of petroleum and coal in industries, thermal plants, home and motor vehicles. In the air, SO 2 combines with water to form sulphurous acid (H 2 SO 3 ) which is the cause of acid rain. It causes chlorosis and necrosis of vegetation. Sulphur dioxide, above 1 ppm, affects human beings. It causes irritation to eyes and injury to respiratory tract. It results in discolouration and deterioration of buildings, sculptures, painted surfaces, fabrics, paper, leather, etc.