Following Diwali, air quality in several cities across northern India plummeted to hazardous levels, with AQI readings exceeding 400 in some areas.

Despite measures such as anti-smog guns and construction restrictions in cities like Delhi, pollution levels remain critical, fuelled by stubble burning and firecrackers, and intensified by the onset of winter.

The question remains: How is the AQI calculated, and what factors contribute to its sharp decline, especially during winter?

Watch the full video to know more.