Tuesday brought citizens of the world's most polluted city found themselves inhaling extremely polluted air that fell into the "severe" level.
Multiple areas of Delhi showed an air quality index above 500, which translates to ten times the recommended level recommended by the global health authority.
In some locations, concentrations of toxic particulate matter soared to of 1,800, equating to fifteen to twenty times higher than safe standards.
For the past four years, the government had enforced a total prohibition on the distribution and bursting of pyrotechnics during the Festival of Lights due to their major role to the dangerous pollution that covers the capital as colder weather begins.
Yet recently, the newly elected city leadership appealed to the judicial authority to propose a modification of the prohibition.
The suggestion was allowing "eco-friendly fireworks" – which have been criticized by environmentalists as being only roughly 30 percent lower impact – as a balance between "cultural practices and environment".
Much to the frustration of medical and ecological activists, the court approved the proposal, stipulating that eco-friendly pyrotechnics could be ignited during limited hours throughout the Diwali.
On Monday night, there was considerable flouting of the time restrictions across the metropolis, with minimal enforcement regarding whether the firecrackers being used were actually the eco-friendly variety.
Several monitoring devices throughout the capital showed air quality peaking around late evening to some of the worst levels recorded during Diwali in at least three years.
The widespread use of fireworks during the celebrations also initiated a blame game with adjacent Pakistan, with representatives in Pakistani Punjab pointing to worsening air quality in Lahore on hazardous particles originating in neighboring India following the celebrations.
Alarmingly severe readings of pollution in Delhi have remained as a serious issue for over a decade and a half, with the situation continuing to worsen.
Around the festival period, the concentration of hazardous particulate matter in the air has been documented to spike to significantly exceeding the worst readings ever recorded in China's capital, which was previously regarded as the globally most contaminated metropolis.
The situation in the city is attributed to a combination of multiple factors including automobile exhaust, construction debris, construction activities, garbage fires and smoke from agricultural fires in neighbouring regions of Punjab and Haryana.
Within these states, farmers regularly ignite agricultural waste to expedite field preparation, creating hazardous pollution that then gets trapped over the metropolitan area as cooler air descends.
Both financial and medical impact on the nearly 33 million inhabitants calling home the capital region is substantial, according to multiple studies.
This pollution causes increased incidence of neurological, cardiovascular and breathing conditions, and can result in oncological diseases.
Environmental contamination is projected to be responsible for approximately 10k untimely fatalities each year in the city.