With the number of vehicles sky rocketing and pollution-levels become worse, a smong-filled atmosphere appears to have become a permanent feature in the capital.With this view, the Centre for Science and Environment(CSE) organised a three-day workshp.The workshop was attended by a number of experts from the United States, Japan and Pakistan to deliberate on air pollution. They discussed how to build an air quality index system, a device that would measure the quality of air in the atmosphere.