Delhi witnessed a less polluted Diwali in 2017 compared to the previous year but low level of cracker activity this year did not have a lasting impact on air as PM2.5 and PM10 levels in the Capital witnessed a two-fold hike on the festival day compared to the week that preceded it.
The findings form part of a study conducted by the Central Pollution Control Board (CPCB) submitted to the Supreme Court on Friday. The study was conducted by a Committee, chaired by Chairperson of CPCB and comprising experts from National Physical laboratory, Defence Institute of Physiology and Allied Sciences, Indian Institute of Technology (Kanpur), Fire Development and Research Centre (Sivakasi and Nagpur), National Environment Engineering Research Institute, scientists from State Pollution Control Boards and health experts from Maulana Azad Medical College (MAMC).
On an analysis of air samples recorded on days prior to Diwali and Dussehra, the same was compared with the samples collected on the festival days and days that follow to assess the change in air quality. The results indicated that on Diwali day, PM 10 and PM 2.5 levels recorded two to three fold higher than the corresponding levels recorded the previous week. However, the silver lining was that the PM 2.5 levels reduced by 39 per cent compared to the Diwali day of 2016.
Further, the study revealed that the harmful and noxious gases of sulphur dioxide (SO2) and nitrogen dioxide (NO2) on Diwali was within standard limits across all locations in the Capital. However, concentration of Aluminium recorded four to six times high than the critical value of 40 microgram per cubic metre. But as compared to previous year, sulphur levels dropped by 20 per cent, potassium by 30 per cent, and strontium, iron, barium by over 50 per cent.
High metal levels were also reflected in urine samples, reported MAMC health experts during Diwali days that could be attributed to fire crackers. However, it added, a long term study alone could assess the long term impact on health due to firecracker bursting.
The bench of Justices AK Sikri and Ashok Bhushan directed CPCB to come out with a comprehensive study indicating the larger impact due to fire crackers that would enable the Court to decide on whether a total ban on firecrackers across the country was essential in public interest.