A day after Diwali firecrackers, Delhi ranked as 'World's Most Polluted City' by Swiss firm IQAir

New Delhi: New Delhi was ranked the world’s most polluted city on Friday morning, November 1, a days after Diwali celebrations pushed air quality to hazardous levels, according to Swiss firm IQAir.

Despite a ban on firecrackers, many residents celebrated with fireworks, adding to the thick smog that covered the city. The air quality index reached 388 at Anand Vihar station at 10am, according to National Air Quality Index or AQI by the Central Pollution Control Board. This is categorised as “very poor”, raising health concerns for residents.

Key areas, including Anand Vihar, saw the AQI plunge into the "severe" category while PM2.5 concentrations soared, creating hazardous conditions for respiratory health. In contrast to the clearer sky on Diwali last year, when favourable conditions kept the AQI at 218, this year's celebrations returned the city to its notorious pollution levels, a pattern worsened by unfavourable meteorological conditions, stubble burning and vehicular emissions.

Although the city government had set up 377 enforcement teams and spread awareness through local associations to ensure compliance with the firecracker ban, neighbourhoods across east and west Delhi reported large-scale flouting of the restrictions.

The city's 24-hour average AQI was recorded at 330, up from 307 the previous day. The smog-laden sky brought back memories of the "severe" pollution in 2020 as the PM2.5 and PM10 levels surged to 145.1 and 272 micrograms per cubic metre respectively at 9 pm. These fine particles, which easily penetrate the respiratory system, pose serious health risks, especially for children, the elderly and those with pre-existing respiratory conditions. In an effort to combat the spike in pollution, the Delhi government had enforced a comprehensive ban on firecrackers for the fifth consecutive year, prohibiting their manufacture, storage, sale and use. Delhi Environment Minister Gopal Rai mobilised 377 enforcement teams, working closely with resident welfare associations, market committees and social organisations to ensure compliance. Police teams were deployed to monitor neighbourhoods, with officials warning that legal action would be taken against violators under provisions of the Bharatiya Nyaya Sanhita (BNS) for defying government orders.

However, reports indicated widespread defiance of the ban across east and west Delhi, with firecrackers lighting up the sky in areas such as Jaunapur, Punjabi Bagh, Burari and East of Kailash. Delhi's surrounding regions, including Noida, Ghaziabad and Gurugram, fared somewhat better, remaining in the "poor" AQI category, while Faridabad recorded a relatively moderate AQI of 181. Yet, unfavourable meteorological conditions, paired with emissions from vehicles, local pollution and stubble burning in neighbouring states, exacerbated the smog over Delhi-NCR, a phenomenon that peaks in winter. According to the Delhi Pollution Control Committee (DPCC), the highest pollution levels are anticipated in early November as incidents of stubble burning in Punjab and Haryana are expected to rise. Over the years, Delhi has seen fluctuations in the air quality on Diwali, recording an AQI of 312 in 2022, 382 in 2021 and 414 in 2020. Despite repeated government efforts to curb the use of firecrackers, the city's air pollution continues to spike during the festival.

The Delhi sky lit up on Thursday as people celebrated Diwali defying a ban on firecrackers. Areas including Lajpat Nagar, Kalkaji, Chhatarpur, Jaunapur, East of Kailash, Saket, Rohini, Dwarka, Punjabi Bagh, Vikas Puri, Dilshad Garden, Burari and many other neighbourhoods of east and west Delhi saw firecrackers being burst. At 9 pm, Delhi's Air Quality Index (AQI) was recorded at 327, with Alipur, Anand Vihar, Ashok Vihar, Aaya Nagar, Bawana, Burari, Mathura Road, IGI Airport, Dwarka, Jahangirpuri, Mundka, Narela, Patparganj, Rohini, Shadipur, Sonia Vihar, Wazirpur, Mandir Marg, Nehru Nagar, Najafgarh and other weather-monitoring stations witnessing "very poor" air quality, according to the Sameer app that provides hourly updates of the National AQI published by the Central Pollution Control Board (CPCB).

With the 24-hour AQI recorded at 328 at 4 pm, Delhi experienced its worst air quality on Diwali in the last three years. Following the practice of the last four years, the city government announced a comprehensive ban on the manufacture, storage, sale and use of firecrackers earlier this month. Delhiites woke up to a sky shrouded in a thick layer of smog on Diwali morning as the air quality continued to deteriorate, remaining in the "very poor" category with a recorded AQI of 328 at 4 pm.

Last year, the citizens of the capital enjoyed a clearer sky and abundant sunshine on Diwali, with an AQI of 218, compared to 312 in 2022, 382 in 2021, 414 in 2020, 337 in 2019, 281 in 2018, 319 in 2017 and 431 in 2016, according to the CPCB. Last year, a decrease in stubble-burning incidents and rain before Diwali, along with favourable meteorological conditions, prevented the capital from turning into a gas chamber after the festival. The pollutant PM2.5 level was recorded at 144 micrograms per cubic metre at 8 pm. The PM10 level was 273 micrograms per cubic metre, according to the CPCB's data. PM2.5 is a fine particulate matter capable of penetrating deep into the respiratory system and triggering health problems, whereas PM10 is a particulate matter that is 10 micrometre or less in diameter.

These tiny solid or liquid particles suspended in the air can be inhaled into the lungs. In Delhi's neighbouring areas, such as Faridabad, Greater Noida, Ghaziabad, Gurugram and Noida, the air quality was slightly better, falling in the "poor" category. An AQI between zero and 50 is considered "good", 51 and 100 "satisfactory", 101 and 200 "moderate", 201 and 300 "poor", 301 and 400 "very poor", 401 and 450 "severe" and above 450 "severe plus".

On Diwali eve, Delhi Environment Minister Gopal Rai announced that 377 teams were formed to enforce the ban on firecrackers across the national capital. He said authorities were in touch with resident welfare associations, market associations and social organisations to spread awareness. Police teams were also formed to ensure that firecrackers were not burst. "Legal action will be taken against those found bursting crackers. They may also be booked under the relevant sections of the BNS (Bharatiya Nyaya Sanhita) for violating government orders," an officer had said. Unfavourable meteorological conditions, combined with vehicular emissions, paddy-straw burning, firecrackers and other local pollution sources, contribute to hazardous air quality levels in Delhi-NCR during winters.

According to a Delhi Pollution Control Committee (DPCC) analysis, the city experiences peak pollution from November 1 to November 15, when the number of stubble-burning incidents increases in Punjab and Haryana.