Tuesday brought residents of the planet's dirtiest urban center were faced with exposed to extremely polluted air that registered in the "alarming" level.
Various sections of the city registered an air quality index exceeding 500, which equals ten times the healthy level established by the global health authority.
Certain monitoring stations, concentrations of PM2.5 and PM10 soared to of eighteen hundred, amounting to 15-20x exceeding safe limits.
For the past four years, officials had implemented a comprehensive restriction on the distribution and bursting of pyrotechnics during celebrations due to their substantial impact to the deadly pollution that blankets the city as the cold season sets in.
Yet earlier this year, the current local leadership appealed to the supreme court to request a relaxation of the ban.
They proposed allowing "environmentally conscious pyrotechnics" – historically doubted by environmental experts as being only about 30% less polluting – as a middle ground between "heritage and public health".
To the disappointment of public health and environmental advocates, judicial authorities agreed to the appeal, mandating that environmentally conscious fireworks could be ignited during limited periods throughout the Diwali.
On Monday night, there was considerable disregard of the regulated periods across the metropolis, with insufficient monitoring regarding whether the firecrackers being used were actually the eco-friendly variety.
Many air quality sensors throughout the city recorded air quality spiking around late evening to the most severe levels seen during the festival in at least three years.
The proliferation of firecrackers during Diwali also sparked a dispute with bordering Pakistan, with authorities in Pakistan's the Punjab region partially attributing worsening air quality in Lahore on pollutants coming from across the border following the festivities.
The dangerously high readings of atmospheric toxins in Delhi have continued as a major problem for more than 15 years, with the condition continuing to worsen.
Near celebratory seasons, the concentration of toxic particles in the air has been found to increase dramatically to 70% higher the peak records ever measured in China's capital, which was formerly regarded as the world's most polluted urban center.
The situation in the city is attributed to a convergence of various sources including automobile exhaust, airborne particles, building projects, rubbish burning and pollutants from agricultural fires in neighbouring areas of farming communities.
Throughout these areas, rural residents regularly set their fields on fire to expedite field preparation, producing dangerous pollution that then gets trapped over the city as colder air arrives.
Public health and economic impact on the nearly 33 million people calling home the capital region is enormous, according to multiple research.
This pollution leads to high levels of nervous system, heart and circulatory and lung conditions, and can potentially cause oncological diseases.
The pollution is estimated to be responsible for 10,000 premature deaths annually in Delhi.