Diwali celebrations coincide with worsening air. Here’s how to stay safer

Diwali celebrations in South Asia, especially northern India, coincide with the return of hazardous winter air.

An estimated 1 billion people worldwide celebrate Diwali.

Fireworks set off during Diwali can make already polluted air more dangerous.

Delhi's fine particle pollution averaged about 19 times the WHO's annual guideline last year.

last year: Delhi's fine particle pollution averaged about 19 times the WHO's annual guideline · in recent years: Air pollution monitors in Delhi reached the maximum reading they can display multiple times · as Diwali approaches: Experts outline ways to reduce exposure to polluted air during the holiday · Sunday: Diwali, the holiday featuring fireworks, begins

1 billion Diwali celebrants worldwide · 19x Delhi's pollution vs WHO guideline · 201–500 India's AQI health categories · 95% N95 filter efficiency · 20 million Delhi's population