Delhi needs to cut pollution level by 65% for clean air
Even as air pollution levels in the national capital have shown a declining trend, Delhi needs to reduce the annual average of PM 2.5 levels by 65% to meet the clean air standards under the National Clean Air Programme (NCAP), the Centre for Science and Environment (CSE) said in an analysis report released on Friday.
PM 2.5 is the most critical pollutant in Delhi’s air. It can penetrate deep inside the lungs and affect public health adversely.
The report highlighted that despite the ongoing efforts to control pollution, which has lowered the high PM2.5 levels, it’s a long way to go to meet clean air quality standards.
While the National Ambient Air Quality Standard has set the annual permissible limit of PM 2.5 at 40ug/m3, the annual average of PM2.5 levels in Delhi between 2016 and 2018 has been almost three times the safe limit at 115ug/m3.
As per the report, the Central Pollution Control Board (CPCB) air quality data, submitted to the Parliament, highlighted that the annual average of PM 2.5 levels during the period 2016-18 was 25% lower than the corresponding period of 2012-14.
The analysis report was released during a roundtable session by the CSE on the next steps to be taken under the NCAP. It credited the stabilisation of pollution levels to implementation of initiatives such as the Graded Response Action Plan (Grap) and Comprehensive Action Plan (Cap) in Delhi-NCR.
The Grap was notified in January 2017 to combat various levels of pollution in the national capital. While measures for moderate and poor levels of pollution are implemented during the summer, measures to fight very poor and severe levels of pollution come into play during the winter (October to March). On a scale of 0-500, an AQI value of 301-400 is considered ‘very poor’ and a value above 400 is considered ‘severe’.
Under Grap, measures for ‘severe plus’ or emergency levels of pollution kick in when PM 2.5 and PM 10 levels breach the value of 300 and 500ug/m3, respectively for 48 hours or more.
Cleaning up the vehicle fleet and use of cleaner fuels, tightening of industrial pollution control, phasing out of dirty industrial fuels such as pet-coke, furnace oil and dust control at construction sites, banning of entry of trucks within city limits, among others were the major steps taken under the two plans.
“The decreasing trend is a good sign for a city like Delhi, which has been facing high levels of air pollution. While this level of action has helped in stabilising the problem, much aggressive action is needed to achieve 65% cut in PM2.5 level to meet the clean air targets,” said Anumity Roychowdhury, executive director, research and advocacy, CSE.
Highlighting the limited progress made, the report said the number of severe-plus air quality index (AQI) days witnessed in the city between 2016 -18 was less than 15 days, as compared to 20 to 40 days during 2011-14.
Also, it said the daily pollution peak of PM 2.5 levels during winters of 2016-18 reduced to 7 to 10 times the permissible limits from 13 to 14 times experienced during 2011-14. The daily (24-hour average) permissible limits of PM 2.5 levels are 60ug/m3.
According to the report, the number and frequency of smog episodes are changing over the past few years. A smog episode is defined as three consecutive days with severe levels of pollution.
“During 2011-14, the smog episodes were numerous and frequent and of shorter duration. This has now changed to fewer episodes, which are larger and longer in duration. For instance, during 2016-17 winters, out of a total of 23 days with severe pollution levels, 16 days were consecutive and continuous, forming a mega episode,” it said.
During the winters of 2017 and 2018, the duration of one smog episode lasted for six to nine consecutive days. There were roughly two to three such relatively long smog episodes, the report stated.
“Delhi, as well as other cities, need to be prepared for third-generation action for clean air in terms of implementation, enforcement, compliance, and institutional capacity to implement design rich solutions across all key sectors of pollution,” the report concluded.