Delhi’s air quality deteriorated slightly on Friday, but remained in the “poor” category. The AQI stayed poor with an overall AQI of 216 recorded by Central Pollution Control Board. In the past three days, the capital has been recording a steady rise in pollution levels. AQI has risen almost 100% from 112 points (moderate) on Tuesday, the day before Dussehra. Experts said multiple unfavourable conditions, like low wind speed, influence of stubble burning through northwesterly winds and local emissions from effigy burning were responsible for the spike.