Air quality in Delhi plunged to “severe” levels on the night of Diwali, with the amount of particulate matter (PM) spiking close to 20 times in certain areas, according to data recorded by monitoring stations across the city.
Though the Delhi government claimed the 24-hour average ambient level of pollutants, particularly those associated with vehicles, such as nitrogen dioxide, was low compared to last Diwali, real-time data showed high pollution levels.
Watch Video: Pollution Levels Spike On Diwali Night
An independent real-time air exposure study, where levels of human exposure to pollutants are monitored against the ambient levels, showed particulates jumping to 1,500-2,500 micrograms per cubic metre. The Centre for Science and Environment (CSE), which conducted the study, found alarming peaks in some areas.
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After 8.30 pm, Mayur Vihar Phase I recorded an hourly average level of 1,763 microgram per cubic metre while in Patparganj, it peaked to 2,114 microgram per cubic metre and at Laxmi Nagar, the exposure peaks were about 2,640 between 10.15 pm and 11.15 pm, and after 11.30 pm, it was 2,654 microgram per cubic metre in Old Delhi.
“The official release on Diwali pollution does not capture the peaks in pollutants in the evening, when firecrackers are burst. We monitored that between 5.30 pm to midnight in different areas. The human exposure levels are clearly much higher,” said Anumita Roychowdhury, the in-charge of CSE’s air pollution division. The CSE team added the 24-hour average range of pollutants does not highlight the real-time spikes in pollutants. “We found that the real-time data for Diwali evening showed a spike in PM 2.5 levels… between 8 pm and 12 pm,” said Roychowdhury.
The System of Air Quality and Weather Forecasting and Research (SAFAR), an agency under the Ministry of Earth Sciences, also noted that air quality dipped from ‘very poor’ levels to ‘severe’ on Diwali.
The agency issued an advisory for the next two days. “People with existing heart or lung diseases such as asthma, chronic obstructive pulmonary disease, congestive heart disease or ischemic heart disease should avoid prolonged or heavy exertion. Everyone else should reduce prolonged or heavy exertion. Children, elderly and people with existing lung diseases may experience discomfort while breathing as deeply or vigorously as they normally would.”
At Anand Vihar, the level of PM 10 was at about 2,000 microgram per cubic metre close to midnight, which is 20 times higher than the safe level of 100.
R K Puram recorded PM 10 level of 1,333 at about 1 am. PM 2.5 — finer and more harmful to those susceptible to ailments of the respiratory tract — was at 734 at R K Puram and 619 at Punjabi Bagh, against the permissible limit of 60.
According to Delhi Pollution Control Committee’s monitoring stations, level of particulates at about 9 pm on Diwali remained in the ‘severe’ range near residential areas in Anand Vihar, R K Puram and Civil Lines. The morning after Diwali, Delhi University area had the highest amount of particulates.
The Delhi government maintained that 24-hour average values of sulphur dioxide, nitrogen dioxide and PM 2.5 were lower this Diwali compared to last year, and claimed it was due to a sustained campaign.
“In terms of noise pollution, the change is marginal. But in Punjabi Bagh, there has been a substantial decline… So on both fronts, there has been some respite this year,” said Ashwani Kumar, environment secretary.