This week, thick and toxic smog engulfed India's capital, New Delhi, a city of more than 21 million residents. According to the US embassy, air quality levels have risen to over 10 times the accepted limit. The index used to rate the quality of air is known as PM 2.5, or particulate matter, which this week measured 451 — this is over the standard of 50 for heathy and breathable air.
These pictures capture the surreal scene as the city's residents go about their daily lives amid the toxic environment.
