The two-week odd-even pilot project of the Delhi government to reduce pollution levels in arguably the most polluted city in the world ends today. However, the question remains did it have the desired result and made the air we breathe cleaner?
The Delhi government, which has been using portable machines sent around to monitor air quality at 200 locations, claim pollution is down by 50% compared to previous years, thanks to the “highly successful” odd even formula.
According to the latest ambient air data collected by these mobile teams of Delhi Pollution Control Committee (DPCC) through mobile dust samplers on using the light scattering technique, pollution compared to last year is down by half. However, there is no base data to compare these pollution readings with.
“We have been taking readings of 15-20 spots every day. After January 15, we will do a thorough analysis. However, we do not have base data since this was the first time pollution readings of these spots were taken. So we are relying on the average of the ambient air quality of last year to compare these pollution readings with,” a senior environment department official said.
Pollution data by the various monitoring agencies show that air quality became much better in the second week of January compared to the first week of 2016. Real-time monitoring data of the System of Air Quality and Weather Forecasting and Research (SAFAR) reveal that pollution levels took a dip as the ambitious scheme moved to its second week.
The readings of PM2.5, the tiniest and deadliest particulate matter which affects lungs and enters the blood stream, rose “poor” to “severe” category from January 1. Same was the case with PM10, which are slightly larger suspended particulate matter.
“Very poor” signifies PM 10 and PM 2.5 levels between 351 and 420 and 211 to 252 micro gram per cubic metre. “Severe” is declared when PM 2.5 and PM 10 cross 253, 421 micro gram per cubic metres respectively. Permissible levels of PM (particulate matter) 2.5 and PM 10 are 60 and 100 micrograms per cubic metre respectively.
Official feel that a big reason behind the air quality not improving despite the restriction being in place was that wind speed has fallen consistently since December. Only on January 6 did it pick up. Strong winds have a major role in dispersing pollutants. Humidity, too, had been higher as compared to December. This also led to an increase in the concentration of pollutants.
In the second week, higher wind speeds and drop in moisture content played a crucial role in reducing pollution levels, as corroborated by SAFAR, Central Pollution Control Board and DPCC readings.