On Tuesday morning residents of this heavily contaminated metropolis encountered inhaling severely hazardous air that registered in the "critical" category.
Several parts of the capital recorded an AQI over 500, which equals ten times the recommended limit recommended by the WHO.
Particular areas, levels of PM2.5 and PM10 reached peaks of 1800, equating to fifteen to twenty times higher than safe standards.
Beginning in 2020, authorities had implemented a comprehensive restriction on the sale and use of fireworks during celebrations due to their substantial impact to the deadly haze that covers the city as the cold season sets in.
However in recent months, the newly elected local administration petitioned the highest court to propose a easing of the prohibition.
The suggestion was allowing "green crackers" – historically questioned by environmentalists as being only roughly 30 percent reduced emissions – as a balance between "cultural practices and public health".
Much to the frustration of medical and ecological advocates, judges complied with the request, mandating that green firecrackers could be ignited during limited periods throughout the festival.
On Monday night, there was extensive violation of the time restrictions across the capital, with minimal regulation regarding whether the firecrackers being used were actually the eco-friendly type.
Several air quality sensors throughout the city showed contamination reaching highest levels around late evening to extremely hazardous readings recorded during the festival in at least recent memory.
Extensive ignition of firecrackers during the festival also triggered a blame game with adjacent Pakistan, with authorities in Pakistan's Punjab province partly blaming declining air quality in their urban centers on contaminants traveling from across the border following the events.
Extremely elevated levels of atmospheric toxins in Delhi have continued as a major issue for fifteen-plus years, with the condition showing no improvement.
During Diwali, the amount of hazardous airborne contaminants in the atmosphere has been found to shoot up to 70% higher the most severe readings ever recorded in China's capital, which was previously viewed as the planet's dirtiest urban center.
The problem in Delhi is caused by a combination of multiple factors including heavy vehicle emissions, airborne particles, development work, waste incineration and haze from agricultural fires in neighbouring states of neighboring agricultural zones.
Throughout these areas, agricultural workers regularly set their fields on fire to prepare for next season, generating toxic haze that remains stagnant over the metropolitan area as cooler air sets in.
The economic and health toll on the approximately 33 million people residing in the metropolitan zone is significant, according to multiple research.
These hazardous conditions results in increased incidence of neurological, heart and circulatory and breathing diseases, and can potentially cause cancer.
Air quality crisis is calculated to be causing ten thousand early mortalities each year in the capital.