Q1) What is PSI? PSI stands for 'Pollutant Standards Index'. It is an index developed by the United States Environmental Protection Agency (USEPA) to provide accurate, timely and easily understandable information about daily levels of air pollution. The ambient air in Singapore is monitored through a telemetric network of air monitoring stations strategically located in different parts of Singapore. Air pollutants such as sulphur dioxide, nitrogen dioxide, ozone,...
