Delhi, the capital of India, consistently faces the world's most harmful air pollution, a crisis that contributes to an estimated 2 million deaths annually across India and has caused irreversible lung damage to 2.2 million children in the city. In November 2019, the Supreme Court of India famously described Delhi's air quality as "worse than narak (hell)," a situation that drastically deteriorates between October and February each year.

Key contributors include vehicular emissions (estimated at 41%), industrial pollution, dust, and significant stubble burning, which accounted for 38% of the pollution in November 2023. Major events, such as the "Great Smog of Delhi" in November 2016, saw particulate matter spike far beyond safe levels. In response, the Delhi government has taken measures like shutting schools and offices for a week in November 2021, while the Supreme Court has repeatedly urged central and state authorities to implement strict pollution control measures.