NEW DELHI, Nov. 8 (Xinhua) -- Delhi, the Indian capital city, which was already facing a severe crisis of air pollution over the past couple of weeks, recorded its worst air quality of the year on Thursday morning, after the Diwali festival night when revelers burst toxic firecrackers.
On Thursday morning a thick blanket of smoke engulfed the city and surrounding areas, even as people complained of difficulty in breathing and itching in the eyes.
According to media reports, the air pollution level entered "severe-plus emergency" category due to rampant bursting of toxic firecrackers.
The overall air quality index (AQI) jumped to 574 which falls in the "severe-plus emergency" category, according to data by the System of Air Quality and Weather Forecasting And Research (SAFAR).
The sharp increase in air pollution was mainly caused by rampant burning of firecrackers that had led to the formation of a smoky layer across the country's capital that drastically reduced visibility.
An AQI between 0 and 50 is considered "good", 51 and 100 "satisfactory", 101 and 200 "moderate", 201 and 300 "poor", 301 and 400 "very poor", and 401 and 500 "severe". Above 500 is "severe-plus emergency" category.
A senior official reportedly said that Delhi's AQI entered in severe category at 2:00 a.m. after midnight on Thursday and would continue to remain in severe category until evening.
A "severe plus emergency" air quality index essentially means that even healthy people may suffer from respiratory illnesses on a prolonged exposure to such air, reported the English daily "The Financial Express", and added that this air will seriously affect those with ailments.
The country's apex court, the Supreme Court of India, had allowed people to burst firecrackers from 8:00 p.m. to 10:00 p.m. to celebrate the festival on Wednesday night.
It had allowed manufacture and sale of just "green crackers" which have low emission of light, sound and harmful chemicals.
Despite the court's order, certain places recorded violations where firecrackers were burnt before and after the set timeframe.
