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Killer Pollutant

1. Air Quality Index (AQI) crossed the 1000 mark in some parts of Delhi NCR and public health emergency was enforced.

Air Quality Index Range

Air Quality Condition










Very poor



Above 500

Severe plus  

2. Air pollution becomes critical during winter in Delhi and in some cities of North and Central India.

3. Air pollution refers to the presence of toxic chemicals in the air. These chemicals lower the air quality and damage the ozone layer and causes global warming.

4. It is a serious global public health problem, with half of the worst polluted cities of the World in India.

Which are the causes of air pollution in Delhi?

1. Both natural and human made factors are contributing to the pollution in Delhi.

2. But the occurrence of natural causes is rare and have a local effect compared to human induced causes.

3. In autumn and winter months, large scale crop residue burning in agriculture fields is a major source of smoke, smog and particulate matter pollution.

4. Apart from this, other factors that contribute to pollution are

a. Population growth

b. Increase in vehicles

c. Poor public transport

d. Poor land use pattern

e. Industrialization

f. Electronic waste

g. Ineffective environmental regulations

What are the major air pollutants?

1. The major pollutants include

Sulphur dioxide, Nitrogen dioxide, Ozone, Fluoro carbons, Hydrocarbons, Metals, Toxicants, Particulate Matter (PM) (fly ash, dust and other suspended matter released from power plants and industries).

2. But there are different sources for different pollutants.

3. For Nitrogen dioxide, the primary source is vehicles, especially diesel vehicles, diesel generators, power plants and wherever high temperature combustion of fuel happens.

4. Sulphur di-oxide comes from burning of fuels like Coal that have Sulphur content.

5. Carbon monoxide is emitted when there is incomplete combustion of fuels especially when wood is burnt.

6. Some of the sources are

a) Human source: Mining, Construction, Power plants, Waste incineration, Landfill disposal practices, Industrial work, Agriculture, Smelting.

b) Natural source: Volcanic eruptions, Wildfires, Microbial decaying processes, Radioactive decaying processes, Increasing temperatures

Where can the negative effects of air pollution be seen?

1. It is a major reason for many health issues like

a. Heart or lung disease

b. Aggravated asthma

c. Decreased lung function

d. Increased respiratory symptoms

2. Air pollution, in particular PM 2.5 negatively impacts the environment

a. Visibility impairment

b. Makes lakes and streams acidic

c. Changing nutrient balance in water bodies

d. Depleting nutrients in soil

e. Damaging forests and farm crops

f. Affects diversity of eco systems

g. Causes acid rain

Why is air pollution a concern?

1. Asthma, chronic heart and lung disease, allergy, cancer, minor eye, nose and skin irritation are some of the effects of air pollution.

2. Exposure to PM for a long time leads to respiratory and cardiovascular diseases such as

a. Asthma

b. Bronchitis

c. Lung Cancer

d. Heart attacks

3. Pollution from vehicles releases gases affect the growth of sensitive organs in fetuses like the brain and the heart.

4. IIT Mumbai study revealed that over 80 thousand people above the age of 30 lost their lives in Delhi and Mumbai due to air pollution in 2015, twice the number of lives lost compared to 1995.

5. Air pollution nearly causes almost 1/4th of all deaths in India, particularly due to exposure to PM 2.5

6. According to Lancet study exposure to PM 2.5 can also cause diabetes.

7. A study by Global Burden of Diseases in 2013 stated that outdoor air pollution is the 5th largest killer in India.

a. 9 out 10 people in the world are breathing polluted air.

b. Air pollution is responsible for killing 7 million each year with most of them living in Asia and         Africa.

8. WHO Report 2018 states that

a. Toxic air kills 6 lakh children under 15 years of age.

b. In 2016, many children died from lower respiratory infections.

c. Air pollution affects children more severely due to their vulnerability. Every single death out of 10 is a child.

d. It results in diabetes and affects neurological development in children.

e. Results in adverse birth outcomes such as low birth weight, pre-term birth and small gestational age births.

9. The Centre for Science and Environment (CSE) report states that

a. 30 % of premature deaths are due to air pollution, cancer and mental diseases.

b. By 2020, more than new 1.7 million cancer cases will be recorded due to air pollution, alcohol         and tobacco.

c. Also air pollution might be related to mental health.

Who are all taking steps to tackle this?

Government of India

1. Steps taken by the Government of India include

a. Introduction of Euro VI by 2020

b. Launching of LPG scheme for cooking

c. Stringent norms for industries have been imposed.

2. Prime Minister’s Office is also monitoring the situation on a daily basis.

3. Major focus is on industrial clusters and traffic corridors, and efforts of Governments of Delhi, Haryana and Punjab.

Government of Delhi

Steps taken by Government of Delhi include

a. Rolling out of the 3rd edition of odd even road space rationing scheme for a 12-day period.

b. Banning of generators.

c. Sprinkling water on roads to suppress the dust particles.

Supreme Court

1. SC has banned construction activity in Delhi temporarily.

2. It also banned burning of crackers in Delhi.


1. Uttar Pradesh government banned the burning of stubble by the farmers in Lucknow.

2. Focus on electric mobility and modernization of fleets is given.

3. Waste to energy plants are also been gaining attention.

How air pollution and climate change linked to each other?

1. The main sources emitting CO2 not only result in air pollution but also drive climate change.

2. Increase in Carbon also leads to stunting of plant’s growth, which promotes accumulation of Carbon dioxide in the atmosphere.

3. Air pollutants sustain climate change by blocking the sunlight.

4. Emission sources are common for pollutants and green-house gases.

5. Nitrogen oxides, carbon monoxides, volatile organic compounds released from cars and factories react with sunlight and form ozone.

6. The resulting high levels of ozone leads to

a. Decreased lung function

b. Reduced crop yield like wheat

7. Climate also plays a role in sustaining pollution.

8. Climate change by influencing behavior of atmosphere and weather systems, impacts air flow and changes the way in which pollutants are dispersed.

9. For example,

a. Stagnant weather increases the intensity and duration of pollutants.

b. Climate change affects pattern of precipitation. Lesser rain leads to longer stay of pollutants.

10. So, more research is needed to understand climate change and air pollution for formulating better strategies.