The odd-even plan of the Delhi government may have reduced congestion on the Capital’s roads with the AAP government celebrating the “success” of its odd-even scheme on Sunday but data shows the city’s air quality worsened during the 15-day trial which ended on January 15.
According to web portal IndiaSpend’s air-quality monitoring devices, air-pollution levels in the city went up by 15% during the 15-day period when the odd-even plan was in effect, when compared to the last 15 days of 2015 (till December 31, 2015).
The average concentration of PM2.5, the study revealed, was 309 during the odd-even period while in the previous 15 days, the average was 270.
PM2.5 is the tiniest and deadliest particulate matter which affects lungs and enters the blood stream.
A detailed look into the weekly average readings at three locations of Sarvodaya Enclave, India Habitat Centre and Munirka revealed that PM2.5 levels dropped by 37% in the second week of January when compared to the first.
This decrease in the second week was primarily because of higher wind speeds and drop in moisture content, which played a crucial role in reducing pollution levels, say experts.
However, according to the portal’s readings, this reduction came after a 50% increase in PM2.5 level in the first week of January (after the odd-even scheme kicked in) when compared to the last week of December 2015.
PM 2.5 readings were above 250g/m³, which is deemed as “severe”, on 11 out of the 15 odd-even days. The remaining four days witnessed “very poor” conditions.
“Very poor” signifies PM10 (suspended particulate matter slightly bigger in size) and PM2.5 levels between 351 and 420 and 211 to 252 micro gram per cubic metre respectively.
The particulate matter pollution is deemed “severe” when PM 2.5 and PM 10 levels cross 253 and 421 micro gram per cubic metres marks respectively. Permissible levels of PM 2.5 and PM10 are 60 and 100 micrograms per cubic metre respectively.
In comparison, five out of the 15 days in the end of December had “very poor” PM2.5 levels, while the remaining 10 days witnessed “severe” conditions.
A TERI study of the four Delhi Pollution Control Committee stations at Mandir Marg, RK Puram, Punjabi Bagh and Anand Vihar, however, showed that there was a marginal drop in pollution levels, thanks to the odd-even scheme. Sumit Sharma, fellow, TERI, said meteorology and emissions are responsible for the air quality.
“Low wind speed ensures that air pollution doesn’t disperse. In the second week of the odd-even scheme, there was more horizontal as well as vertical dispersion and thereby there was a decline in pollution levels. On January 13, due to Lohri, the air again became fouler,” Sharma said.
He, however, did not provide the exact readings from the monitoring stations.