New Delhi woke Monday to thick smog after Diwali firecrackers on Sunday, with air quality in parts of the capital in the severe range, Al Jazeera, Deutsche Welle and The Hindu reported^1,2,3.

Al Jazeera said the Air Quality Index exceeded 350 in several neighborhoods Monday morning, a level it described as severe against World Health Organization exposure thresholds¹. DW said several parts of Delhi and surrounding satellite cities in the National Capital Region also logged severe-category readings and that haze cut visibility over roads and high-rises². The Hindu, citing the Central Pollution Control Board live dashboard, said the citywide AQI reached 404 at 4 a.m. Monday before easing, with Burari Crossing at 441 and Vivek Vihar at 437 among the highest listed stations³.

Residents set off firecrackers throughout Sunday evening despite restrictions, all three accounts said^1,2,3. India's Supreme Court last month limited conventional firecrackers and allowed only approved green firecrackers in three-hour windows on Saturday and Sunday, Al Jazeera reported; those products still emit particulate matter¹. The Hindu said fireworks continued past a 10 p.m. deadline on Deepavali night³. DW said the court limits did not hold in practice and that green crackers still emit 65 to 70 percent of the pollution from conventional ones².

DW, citing IQAir data from a government monitoring station as reported by AFP, said PM2.5 at Mandir Marg in central Delhi reached 879 micrograms per cubic meter early Monday, nearly 59 times the WHO daily guideline of 15 micrograms². Al Jazeera did not publish that station reading; it said pollution days before Diwali had already surged to more than 30 times the WHO daily limit¹. The Hindu did not cite the Mandir Marg IQAir figure³.

The metropolitan region of about 30 million people often ranks among the world's most polluted capitals in winter, Al Jazeera and DW said, when cooler, still air traps emissions^1,2. Al Jazeera cited India's environment ministry as attributing 23 percent of winter pollution to vehicles and 20 percent to biomass burning, including farm stubble fires¹. DW named vehicular emissions, crop-residue fires in neighboring states and industry as the recurring mix².

DW said winter pollution rules in New Delhi took effect Nov. 1, including vehicle restrictions and construction bans, and that Saturday had the worst Diwali-eve air in a decade². The Hindu said Commission for Air Quality Management Stage III GRAP measures remain in force across Delhi and adjoining districts of Haryana, Uttar Pradesh and Rajasthan, with CPCB classifying 401-500 as severe³. Al Jazeera noted haze can linger for days when winds are weak¹.