Diwali pollution in Delhi getting worse over years, says report
The Central Pollution Control Board (CPCB)’s latest report on air and noise pollution over the years during Diwali in India spells bad news for Delhi.
In the report -- ‘Deepawali Festival Monitoring Report 2016,’-- the CPCB has provided comparative data for 2014 to 2016 by measuring ambient noise levels and air quality standards on a ‘normal day’ (six days before Diwali) and on the day of the festival for multiple locations across India.
Most of Delhi had noise and air pollution problems even on ‘normal days’ but it was seen to spike on Diwali, especially last year.
Experts blame weather phenomena for the foul air that followed Diwali last year, when the city was enveloped in a dense cloud of smog.
AIR QUALITY ON DIWALI
In 2016, the PM10 level ranged between 203 and 318 μg/m3 in different parts of the Capital before the festival. The acceptable standards are 100 μg/m3.
This spiked to over 1,000 μg/m3 in areas such as Pitampura and Parivesh Bhavan in east Arjun Nagar on Diwali.
The data shows the situation has been getting worse over the years. In 2014, a normal day’s PM10 levels were recorded between 115 and 152 μg/m3. This increased to 119 to 166 μg/m3 in 2015.
Similarly, festival day readings in 2014 ranged between 442 and 756 μg/m3, and 460 and 593 μg/m3 in 2015.
WHO IS TO BLAME?
This foul air was attributed to weather conditions like slow wind speed on the day of Diwali, which dropped to 1.3 m/s in 2016, while it averaged around 3.4 m/s in 2015.
The pollutants were caught closer to the ground in 2016 because of wind patterns, as compared to 2015. The mean the mixing height during last year’s Diwali day was 492 metres while the previous year it was 590 metres. At night, it dropped to 152 metres in comparison with 2015’s 324 metres.
According to Dipankar Saha, head of CPCB’s air lab, lower temperature coupled with lesser wind speed helped stagnation of pollutants.
“This is due to cooling of the earth’s surface and the air closer to the ground tends to cool down as well as. If the wind speed and the mixing height is low, the pollutants remains suspended close to the ground,” he said.
On a normal day, the noise level ranged between 43 and 74 Leq.dB(A) in 2016 while it ranged between 74 and 80 Leq.dB(A) on the day of Diwali.
Mayur Vihar Ph-II was the noisiest on Diwali 2016, where noise levels hit 80 Leq.dB(A).
Noise levels on Diwali day have reduced in areas such as Kamla Nagar and Janakpuri over the years, while it has remained the same in areas such as Lajpat Nagar and Okhla.