The Supreme Court’s ban on sale of fire crackers in Delhi nealy halved the noise levels on Diwali, according to data from the Central Pollution Control Board (CPCB).
Generally, the noise from crackers peaks on Diwali evening and the CPCB’s noise-measurement tools — stationed across selected residential and industrial units in Delhi — record between 83 to 86 decibels (dB) in Mayur Vihar and Okhla. These are the two locations where data has been systematically compiled since 2013.
This year, however, both locations registered a dip of three to five dB.
Noise levels are measured on a logarithmic scale and a three db fall roughly corresponds to halving of noise levels.
“Sound level data on Diwali day, monitored over the last four years, reveals that 2017 recorded the lowest levels at all stations,” said the report.
‘Drop due to the ban’
The sharp dip comes even as measurements made by the CPCB on days leading up to Diwali show that noise levels across 10 stations this year were in most cases higher than last year. They hovered between 66 and 45 dB.
“In general, pre-Diwali noise would slightly increase as the average population in a place would generally rise,” said D. Saha, who leads air quality measurements at the CPCB.
“The drop in noise this year is entirely due to the reduction in bursting of crackers,” he added.
This year, the CPCB recorded ambient noise levels at more than 200 locations and ambient air quality at about 170 locations across India. In Delhi, ambient noise was monitored at 16 locations and ambient air quality at 18 locations. The monitoring was carried out in two phases: pre-Diwali (from October 12) and Diwali day.