By devising a scientific methodology, these parameters are combined into a single quantitative measure called Air Quality Index (AQI) to assess overall air quality.
The air pollution in Delhi NCR, especially in winter months, is mainly contributed to by heavy concentration of PM 2.5 (ultra-fine) and PM 10 (coarse-dust) particles, and gases like carbon dioxide, carbon monoxide, methane and nitrous oxides, among others. By devising a scientific methodology, these parameters are combined into a single quantitative measure called Air Quality Index (AQI) to assess overall air quality.
Several factors responsible for air pollution in Delhi NCR are biomass burning (mainly stubble burning in the adjoining states of Punjab, Haryana, Rajasthan and Uttar Pradesh), construction and road cleaning, and transport and industrial/commercial operations. To give an idea of the magnitude of the air pollution generated, nearly 17% of PM 10 and 19% of PM 2.5 pollution is due to agricultural residue burning, 10-11% due to industries, and the remaining comes from other activities. Further, according to a study published by journal Springer, each tonne of crop residue burning releases around 3-kg particulate matter, 1,460-kg carbon dioxide, 60-kg carbon monoxide, 199-kg ash and 2-kg of sulphur dioxide.
Just think, what would happen when many thousands of tonnes of stubble burning is done. In passing, it may also be remarked that a sufficient amount of Delhi NCR’s pollution comes from as far as Pakistan, Afghanistan and Oman, according to a study by TERI, and dust from the Sahara Desert also pushes up pollution levels in Delhi.
Now, with the retreat of the monsoon from the Capital and the harvesting season almost in full swing in adjoining states, the question on our minds is whether we can hope to inhale better quality of air this winter? To my mind, it appears extremely difficult to answer at this juncture. This is simply because the concentration of PM 10 in the air, which was recorded as 35 ug/cubic metre on September 25 this year, is constantly going up, and has now reached the level of 278 in October (in just 10 days)—the safe, permissible limit being 100 only. Similarly, the levels of PM 2.5 had gone up from 101 ug/cubic metre on September 29 to 120 on October 6—the safe limit is 60. Accordingly, the AQI has also shot up from 52 (September 25) to between 302 to 368 in different parts of the Capital on October 6—which is considered to be ‘very poor’ on a scale of 0-500.
This sudden jump is due to calmer wind (sometimes zero speed), moisture decline and loose soil getting suspended in the air. In 2017, Delhi’s AQI increased from 247 (October 8) considered ‘poor’ to 486 (November 9) considered ‘severe’ when Delhi encountered thick and dread fog for over a week, leading to the Delhi government declaring a public health emergency.
However, in the midst of the above despondency, there is a silver lining giving us hope that Delhi NCR’s air pollution can be controlled this year to an extent. This is particularly because a slew of measures have been planned by the Central Pollution Control Board, Delhi Pollution Control Committee, and pollution control boards of adjoining states and also the National Green Tribunal (NGT). Moreover, the Supreme Court-appointed Environment Pollution (Prevention & Control) Authority (EPA) has been empowered with a Graded Response Action Plan (GRAP) to take emergency measures quickly in the Capital to combat and counter sudden air pollution spikes. Let me discuss the details of these measures briefly.
First, through increased manual vigilance, satellite mapping and introducing super straw management system (made mandatory), the nearby states have taken action to stop stubble burning. For example, the Haryana government has told the EPA that it has been able to meet more than 80% of the target it had set to provide agricultural implements to farmers, such as super management systems, happy seeders, mulchers, rotary slashers and rotavators, among others, to control stubble burning.
Similarly, the Punjab government has targeted 40% of 74 lakh acres under paddy cultivation for extracting stubble by using machines. It is noteworthy that crop burning incidents dropped by 46% in 2017 as compared to 2016, and this figure is expected to drop further in 2018. Further, the NGT has imposed fines ranging from Rs 2,500 to Rs 5,000 on farmers to prevent stubble burning. The Union government, too, has sanctioned Rs 1,115 crore to subsidise machinery for in situ management of crop residue.
Second, the three municipal corporations of Delhi and the New Delhi Municipal Council (NDMC) have deployed 83 environment marshals in different municipal wards since January 2018, who have flagged 10,000 cases of open garbage burning and violation of rules at construction sites, helping authorities to take action against violators even by slapping heavy fines. Also, a series of directions including sprinkling of water at construction sites, increased mechanical sweeping of roads and stopping vehicles (not destined for Delhi) from entering the Capital have been issued.
Third, the Delhi government has taken a very important step of installing pollution early warning system (EWS) with the deadline of October 30 for its completion. The EWS would regularly pick up data from 36 stationary air pollution measurement systems (already installed in different parts of the Capital) along with real-time aerosol information from NASA satellites and process it further to make necessary forecasts about air quality. Thus, the EPA would be prepared well in advance when it comes to implementing measures under GRAP. As of now, GRAP measures come into play when air pollution levels have already spiked.
Fourth, industries and restaurants in Delhi had been issued instructions to switch over to approved cleaner fuels such as BS-6 diesel and petrol, natural gas (PNG, CNG), LPG and biogas, with the deadline of September 30, which has ended. The instructions also talk about stern action against defaulters.
To conclude, urgent and honest implementation of the above measures is essential. Only then can one know their real impact on the improvement of the Capital’s air quality and also decide what policy and other actions are needed in the future.
(The author is a former ISS officer and a UN consultant)