Residents in the Indian capital <a href="https://www.thenationalnews.com/world/asia/2023/11/08/delhi-pollution-school-winter-break/" target="_blank">Delhi</a> woke to a thick blanket of smog as <a href="https://www.thenationalnews.com/world/2023/11/12/millions-of-indians-set-diwali-world-record-as-air-pollution-worries-rise/" target="_blank">air pollution</a> reached dangerous levels after fireworks and other pyrotechnic displays set off to mark <a href="https://www.thenationalnews.com/lifestyle/family/2023/11/07/happy-diwali-2023-celebrations/" target="_blank">Diwali</a>, despite a court ban. Average air quality levels in the city were recorded at more than 400 on the Air Quality Index, or AQI, on Monday, according to the Central Pollution Control Board, India’s leading environmental watchdog, after fireworks throughout Sunday and the early hours of Monday morning. A similar air quality situation was seen in Noida, Ghaziabad, Gurgaon and Faridabad. Kolkata, the capital of West Bengal state, was also cloaked in haze as air quality levels were recorded at poor levels, a lingering effect from Diwali celebrations. The Air Quality Index measures the quality of air and the amount of dust and other particles in the atmosphere. Calculations are based on a host of pollutants including levels of nitrogen dioxide and carbon monoxide. In some places, the AQI reached 900 or above. A reading between zero and 50 is considered good, 51-100 is satisfactory and 101-200 moderate. However, 201-300 is considered poor, 301-400 very poor and 401-500 severe. At Delhi's Jawaharlal Nehru Stadium, AQI was recorded at 910, while in Lajpat Nagar the AQI was 959, according to AQI India, a real-time pollution monitoring platform. The city’s pollution levels rose after a slight improvement throughout the weekend due to rain on Saturday making it the best Diwali air quality in eight years, with fireworks and pyrotechnics thought to be a significant factor. The sale of fireworks is banned by the Supreme Court, but residents flouted the ban, despite warnings by authorities that such actions could affect<a href="https://www.thenationalnews.com/world/asia/2023/11/01/delhi-pollution-very-poor/" target="_blank"> air quality </a>levels. Toxic emissions from the displays, along with smoke from farm fires engulfed the city on Monday morning, with visibility significantly dropping. Delhi has experienced high levels of toxic air since October. Authorities have implemented desperate measures to try to bring air pollution levels down. Schools have been government offices have been closed, water sprinklers have been installed and construction and heavy vehicles have, at times, been banned. An<a href="https://www.thenationalnews.com/world/asia/2023/11/06/delhi-mumbai-air-pollution/" target="_blank"> odd-even traffic</a> restriction plan that would allow vehicles with odd and even number plates to travel on alternate days to curb pollution was also considered. The plan has been shelved, however. Following Diwali celebrations, many residents have complained about congestion, headaches, burning eyes and itchy throats as a result of the air quality. “I am unable to breathe. My nose and eyes are burning. It is a difficult situation,” Chayanika Nigam, a Noida resident, told <i>The National.</i>