The advisory pointed out that while a normal adult breathes approximately six litres of air per minute at rest, during exercising it increases to 20 liters. With the current level of air pollution in Delhi and NCR, this increases toxins in lungs. “Exercise areas should be at least 200 meters away from roads, construction sites and smoke-emitting industry,” advisory says, adding that “even this does not guarantee clean air”. On Wednesday, Delhi-NCR recorded hike in the PM2.5, or particles with diameter less than 2.5mm, ranging between 392 to 326 units, as compared to 362 to 302 units on Tuesday, according to the data from all ten monitoring stations of System of Air Quality and Weather Forecasting and Research (SAFAR). Safe limit for PM2.5 is 60 units as per tiol standards and 25 units as per intertiol standards.(IANS)