New Delhi, Nov 11: Delhi's air quality witnessed a gradual regression on Diwali due to bursting of fireworks, with few areas of the city recording 'critical' level of pollution, while the rest fell largely in 'very poor' category on the air monitoring scale.
As the day progressed, suspended particulate matters (PM 2.5 and 10) shot up to unhealthy levels across the capital, leading to the World Air Quality Index issuing a health alert, due to the potential "serious health effects", especially among patients, children and the elderly.
The IGI Airport station of System of Air Quality, Weather Forecasting and Research (SAFAR) showed PM 2.5 and PM 10 readings at 325 microgram per cubic metre and 452 microgram per cubic metre respectively at around 3 PM.
The corresponding safe limits stand at 60 microgram per cubic metre and 100 microgram per cubic metre. PM 2.5 are extremely fine particulate matters, with a diameter smaller than 2.5 microns, that can penetrate deep into the respiratory tract and cause harm to the lungs.
PM 10 are comparatively larger but also have the potential to cause health effects. In northwest Delhi's Pitampura, an area which has consistently shown high levels of pollution, PM 2.5 was at 303 and PM 10 at 297, 'very poor' by prescribed standards during the same time.
As per real time data of Delhi Pollution Control Committee, at Anand Vihar, PM 1O was at 490 at 2 PM. The corresponding figures of Mandir Marg, Punjabi Bagh and RK Puram were 207, 207 and 302 respectively.
The meteorological department had cautioned that pollution level during Diwali night would be "severe" due to fireworks and bursting of firecrackers and advised those persons with heart and lung diseases to stay indoors.
In all likelihood, air quality during Diwali-2015 is going to be inferior to that of Diwali-2014 owing to cooler temperature and downward shift of inversion layer, SAFAR's Project In-charge, Gurfan Beig, said.
The PM (particulate matter) 2.5 level is expected to be 148 per cent on November 12, the day after Diwali, and 170 per cent in case of PM 10. Noida, Delhi University (North) are expected to record high level of pollution while Lodi Road and Mathura Road will witness less pollution, SAFAR said.