A recent study by the Centre for Science and Environment (CSE), a New Delhi-based organisation, has revealed alarming findings about the ozone levels in the National Capital Region of India. Despite lockdowns due to the COVID-19 pandemic, there has been a significant increase in the number of days and areas experiencing prolonged periods of high ozone levels. Strikingly, these levels have crossed the permissible limits even during the winter.
Understanding Ozone
Ozone, which is composed of three atoms of oxygen, is both a naturally occurring and man-made gas. It exists both in the Earth’s stratosphere and at ground level. Ozone has a dual role in the environment and human health – it can be both beneficial and harmful.
The ‘good’ ozone present in the Earth’s stratosphere layer essentially serves as a protective shield, shielding humans from harmful Ultraviolet (UV) radiation. However, ground-level ozone poses threats to human health. Its highly reactive nature can have adverse effects, particularly on individuals suffering from respiratory conditions and asthma.
The Problem of Smog
Air pollution that reduces visibility is referred to as smog. The term originated in the early 1900s, and it was used to denote a mixture of smoke and fog. This type of pollution is common in industrialised areas and remains a significant issue in many of today’s cities. Majority of the smog experienced today is Photochemical Smog, a by-product of chemical reactions between sunlight, nitrogen oxides (NOx), and volatile organic compounds (VOCs) in the atmosphere.
Ozone: A Year-Round Menace
Contrary to the idea that Ozone is predominantly a summer concern, recent findings indicate that the gas has become a disturbing issue during winter as well. Although city-wide averages mostly remain within the standard limit, the number of ‘good’ category days in Delhi fell to 115 in 2020, 24 days fewer than that of 2019. A detailed analysis shows that the areas exceeding the eight-hour average standard are widespread in the city.
Government Efforts and Suggestions for Improvement
The study suggests that the transport sector is the major contributor to NOx and VOCs. Therefore, significant action is required against high emitters of these gases, including vehicles and various industries. The Government has taken measures such as the introduction of BS-VI vehicles, a push for electric vehicles, and the implementation of the Graded Response Action Plan and the National Clean Air Programme.
However, there is a pressing need for refining a clean air action plan, incorporating strategies for ozone mitigation, strengthening actions on vehicles, industry and waste burning. It’s crucial to adjust the Air Quality Index to reflect the most polluted eight-hour average of the day and to include alerts based on the worst affected area, aligning with global best practices.