Top 25: Delhi's air quality improves to 'very poor' ahead of Diwali

Wind directions changed by Tuesday noon, creating an outlet for the toxic air over the Delhi-NCR region and thereby improving the air quality to "very poor," from "severe" in the morning and "emergency" a day before.

Coarser and highly dangerous PM2.5 or particles with diameter less than 2.5 mm continue to dominate the pollution factor in Delhi, and are still at least four times higher than the national standards and nine times the international standards.