ANSWER: 2.5
Explanation:
In seven out of 10 monitoring stations of the Central Pollution Control Board, PM 2.5, particulate matter having the size equal to or less than 2.5 micron, came out to be the major pollutant. PM 10 had greater presence in some areas such as Anand Vihar. Air Quality Index (AQI) of System of Air Quality and Weather Forecasting and Research (SAFAR) stations, located across the city, also remained between very poor and poor. Permissible levels of PM (particulate matter) 2.5 and PM 10 are 60 and 100 micrograms per cubic metre respectively and consistent exposure to any value above this is harmful as particles embed themselves deep inside the lungs.
