News Excerpt
Delhi’s air has registered a sharp deterioration in Air quality. The smog and existing pollution level in the city exceed the standard level of pollutant.

•    Every year during the onset of cold weather in the Capital, Air quality has its ominous adverse impact.
•    The Centre for Science & Environment (CSE) stated that Air pollution is five times higher than the national standard and increasing number of vehicles is the biggest contributing factor for rising air pollution.
•    According to a CSE release, particulate matter in Delhi air has registered a rise of 47 per cent between 2000 and 2011. Nitrogen dioxide levels too leapt by 57 per cent during the period. Delhi’s air has shown presence of high levels of nitrogen dioxide, carbon monoxide, ozone, and benzene.

    Smog consists of smoke and fog. Smog is a mixture of many pollutants. Smog is common in industrial areas. Today, most of the smog we see is photochemical smog. The smoke usually came from burning coal and fossils.
    The National Capital Region is badly hit, as the burning of agricultural residue in Punjab and Haryana is releasing large volumes of smoke containing, among other pollutants, highly damaging fine particulates, or PM2.5.
    This problem is aggravated by the local anthropogenic factors such as-burning of urban waste, diesel soot, vehicular exhaust, road and construction dust, and fossil led power generation.
    Pollutants
    Primary pollutants are the ones that contribute to smog formation and are emitted directly from the source.
    Secondary pollutants form in the atmosphere by chemical interactions of primary pollutants with normal environmental conditions.
    The key pollutants that lead to air pollution are oxides of nitrogen, especially nitrogen oxides and nitric oxides, which are released in the atmosphere by combustion of fossil fuel coming from coal power plants, factory emissions and car exhausts.
    Nitrogen dioxide is a serious air pollutant, which, on inhalation, causes pulmonary edema (an accumulation of excessive fluid in the lungs). Moreover, it contributes to photochemical smog, thus, causing serious damage to the environment.

Sources of Smog and weightage

Who is Most at Risk from Smog?
    High exposure to smog laden poor Air Quality is known to lead to increased hospitalisation for asthma, lung diseases, chronic bronchitis and heart damage. Long-term exposure can even cause lung cancer.
    The nitrogen dioxide levels can trigger serious respiratory conditions and sudden death syndrome among infants.
    Smog can cause or aggravate health problems such as eye irritation and reduced resistance to colds and lung infections.
    The ozone in smog also inhibits plant growth and can cause widespread damage to crops and forests.
    Physical activity causes people to breathe faster and more deeply, exposing their lungs to more ozone and other pollutants. Group of people are particularly sensitive to ozone and other air pollutants in smog are--
1.    Children: Active children run the highest risks from exposure to smog. Children are also more prone to asthma—the most common chronic disease for children and other respiratory ailments than adults.
2.    Adults who are active outdoors: Healthy adults of any age who exercise or work outdoors are considered at higher risk from smog.
3.    People with respiratory diseases: People with asthma or other chronic respiratory diseases are more sensitive and vulnerable to the effects of ozone. Typically, they will experience adverse effects sooner and at lower levels of exposure than those who are less sensitive.
4.    People with unusual susceptibility to ozone—Some otherwise healthy people are simply more sensitive to the pollutants in smog than other people and may experience more adverse health effects from exposure.

Steps Taken by Government to deal with menace
o    Delhi government had introduced emission control norms for the first time in 1991. Since then, the standards have got stricter in the form of pollution control certificates. Currently, only Bharat Stage-VI (BS-IV) compliant vehicles can be registered in Delhi.
o    Delhi government phased out lead petrol, reduced the amount of benzene in fuel, and introduced low-sulfur diesel to provide vehicles with cleaner fuel. Mitigation measures also involved major infrastructure investments.
o    The most prominent among them, which also tackles traffic congestion, is the creation of mass rapid transport schemes like Delhi Metro, which has taken lakhs of vehicles off the road. It could have taken off 1.4 lakh vehicles from the road and would have made a dent in the current smog scenario.
o    An air ambiance fund has been created to fund mitigation initiatives from money collected from diesel sales.
o    Recently, the court, executive and civil society came together to ban even bursting of crackers in Delhi on Diwali to help reduce the famous after Diwali smog.
o    One more novel scheme tested by the government was an anti-smog gun, the prototype of which was tested by the Delhi government at Anand Vihar, one of the most polluted locations in the capital. The concept is that the gun will shoot a mist of high pressure water into the air, which will capture and immobilize pollutants and particles, making them settle on the ground later.
o    To spread awareness on the dangers of pollution and its mitigation methods, the Delhi Pollution Control Board conducts routine awareness programs and workshops.
o    The tree transplantation policy of the Delhi government mandates 80% of the trees affected by construction and development activities must be transplanted, along with 80% out of them surviving after a year. This is in addition to the mandatory requirement of planting 10 saplings in case one tree is cut for construction purposes, which has helped increase the green cover in Delhi.
o    They have taken steps like starting an anti-dust campaign, using the bio-decomposer technique for stubble burning, launching the electric vehicle policy, announcing the tree transplantation policy, etc, under its 'Yuddh. PradushankeViruddh' anti-pollution campaign.
o    To reduce pollution in the city, the Delhi government is also setting up a smog tower at Connaught Place which will distribute clean air in the national capital.
o    In an effort to reduce the contribution of vehicular emissions to Delhi's PM2.5 concentrations, the Delhi government has introduced the new EV policy. The government is providing subsidies and incentives on their purchase to promote large scale adoption of EVs.

    Measures taken by government had met with varying degrees of success, which aren’t always quantifiable due to the diffuse and multi-source nature of the problem and too many variables at play. A coordinated and unison effort is required instead of fragmented approach.
    Perhaps the most positive action of the government was formation of the SAFAR air quality index, which combines five of the most pressing pollutants into a single air quality index (AQI). This ranges from good to severe and can help in policy formulation as well as precautionary measures. The data and quality of Index is questioned on the ground of WHO’s standard. SAFAR AQI is different from the WHO’s Air quality methodologies. Thus, Contradictory approach invites criticism.   
    The recently introduced smog Gun is unable to cope with the issue. Since the range of this method is low and it’s only effective in the immediate time frame, it can only be used near sensitive locations such as hospitals or schools. There is need to adopt a sustainable and permanent solution.

Way Forward
    It is evident that most of the measures taken against smog and pollution are punitive and ad hoc in nature and address the symptoms and not the root cause of the problem. Actions to tackle the smog problem should be both preventive and punitive.
    To find a permanent and sustainable solution to air pollution and smog, there needs to be a synergy between all levels of policy formulation and implementation from the Delhi government, Centre, National Green Tribunal, judiciary, expert agencies and most importantly people. Also, opinions and considerations from all sections of the society, especially experts of agriculture, environment, chemistry, industry etc. would have to be taken.
    Comprehensive studies, evaluating the pros and cons of personal mitigation devices for a permanent solution to air pollution crisis of Delhi, need to be conducted with a holistic and interdisciplinary approach.

Some Global Instances
    The 'Great Smog of London' or 'The Big Smoke' in 1952 was the most severe air pollution crisis in European history, causing around 8,000-12,000 deaths.
    In 1948 Donora Smog in the US led to formation of Smog clouds, consisting metal dust, sulfur dioxide and carbon monoxide. As a result, around 7,000 residents suffered from various breathing problems and were hospitalised. At least 20 residents died within 5-6 days.
    Similarly, Beijing suffered major air pollution in 2013 due to burning of coal, which caused 366,000 premature deaths.
    The environmental disasters like Smog did not happen in a day. There were many alarming signs, like the ones we are witnessing in Delhi nowadays.

Indoor air quality
    Not only outdoor, but also indoor air quality is a great concern since people consider their homes a safe refuge and become carefree.
    Sources of indoor pollution are VOCs and soot from open air stoves or kerosene stoves; mold and spores from damp places, especially the washroom area, dead skin and insect particles as well as pollen from planted flowers or dustaccumulated in blankets and mattresses.
    This problem is so common that it has been given a special name: Sick Building Syndrome.
    Exposure to such indoor air pollutants maycause allergy, asthma, cardiovascular disease, memory loss, cancer and can be harmful to fetal development.