Tuesday brought citizens of this heavily contaminated metropolis were faced with breathing dangerously toxic air that was classified as the "critical" category.
Multiple areas of the city recorded an air quality index over 500, which equals 10x the safe level recommended by the global health authority.
In some locations, readings of dangerous airborne particles reached peaks of 1,800, equating to fifteen to twenty times higher than acceptable standards.
For the past four years, officials had maintained a total prohibition on the purchase and ignition of firecrackers during Diwali due to their significant contribution to the deadly haze that blankets the capital as colder weather sets in.
Nevertheless in recent months, the current regional government petitioned the supreme court to seek a relaxation of the ban.
The suggestion was allowing "eco-friendly fireworks" – previously criticized by conservation groups as being only approximately one-third less polluting – as a middle ground between "cultural practices and ecological concerns".
To the disappointment of environmental and health campaigners, the court agreed to the appeal, specifying that green firecrackers could be ignited during limited hours throughout the celebrations.
Throughout the festival evening, there was widespread disregard of the regulated periods across the capital, with minimal monitoring regarding whether the firecrackers being used were actually the more environmentally friendly variety.
Several air quality sensors throughout the city recorded air quality peaking around late evening to some of the worst levels observed during Diwali in at least recent memory.
The proliferation of fireworks during the festival also triggered a blame game with neighbouring Pakistan, with representatives in Pakistani the Punjab region pointing to deteriorating pollution levels in Lahore on contaminants originating in neighboring India following the celebrations.
Alarmingly severe levels of atmospheric toxins in Delhi have persisted as a significant problem for over a decade and a half, with the problem continuing to worsen.
During the festival period, the concentration of dangerous particulate matter in the atmosphere has been documented to increase dramatically to seventy percent above the worst records ever measured in China's capital, which was previously viewed as the world's most polluted city.
This crisis in the city is caused by a convergence of multiple factors including automobile exhaust, dust, development work, waste incineration and pollutants from crop residue ignition in nearby states of Punjab and Haryana.
Within these states, farmers routinely burn crop residue to expedite field preparation, creating toxic pollution that remains stagnant over the capital as winter air arrives.
Both financial and medical impact on the nearly 33 million inhabitants calling home the metropolitan zone is substantial, according to multiple investigations.
This pollution results in high levels of nervous system, cardiovascular and lung disorders, and can even lead to cancer.
Air quality crisis is projected to be accounting for 10,000 untimely deaths each year in the capital.
Lena Hofmann ist eine erfahrene Journalistin mit Schwerpunkt auf gesellschaftlichen Entwicklungen und kulturellen Ereignissen in Europa.