Why did Delhi's AQI climb from 124 to 464 in just 96 hours?

Delhi's AQI surged nearly fourfold in 96 hours, rising from 124 on October 30 to 464 by November 3. The brief improvement after October rainfall was reversed as weak winds and dry weather trapped pollutants. Stubble-burning fires in Punjab, Haryana and Pakistan added to the pollution. Notably, authorities have implemented GRAP Stage II measures across NCR.