New Delhi Air Quality Index (AQI) | India

A report by the Environmental Performance Index in 2014 said that a total decline of 100 percent was seen in the air quality of India in the last 10 years and the city that has been hit the greatest is the capital city, New Delhi, India. Research by Berkeley Earth revealed that on an average, when the AQI is in a relatively better state than the usual, breathing that air still means that pollutants equal to the same amount as 31 cigarettes smoke entering your lungs.

With statistics like these, all of us need to be educated and concerned about the rising Delhi pollution level. Learn about the causes and effects of Delhi air pollution so that we can understand the problem and try to bring a change on a personal and public level.

What are the Main Sources & Causes of Delhi Pollution?

There are many causes and sources of Delhi air pollution like stubble burning, vehicle emissions, industrial pollution, construction, cold weather, geographic location, stagnant winds, population growth, Badarpur thermal power plant, fire in Bhalswa Landfills, etc.

1. Agricultural Stubble Burning

Agricultural stubble burning has been the major caterer to the rising air pollution and smog in Delhi. The problem is that as there is a very short time gap between the harvesting of paddy and wheat, the straw from the last harvest needs to be disposed off as soon as possible. The government has suggested the farmers do manual or mechanical management of straw but as the process is expensive and takes more time, farmers switch back to their traditional practice of stubble burning. Thousands of crores have been spent by the Central and the State government of India, a ban has been put on the practice but stubble burning has not come under control yet. The smoke from this agricultural burning gets transported to Delhi because of the westerly winds. According to a study by IIT Kanpur, agricultural burning is the third largest contributor towards particulate matters in Delhi.

2. Vehicular Emissions

It is the number one contributor to the PM2.5 and PM10 particles in Delhi which is 28%. And overall, out of the total air pollution, 41 percent is due to vehicular emissions. Vehicular emissions have a large number of carbon monoxide in them. Long exposure to it can cause death and more and more vehicular emission is causing CO to accumulate in our atmosphere.

3. Industrial Pollution

Delhi has the highest number of small-scale industries in India and they do not respect any limits on the emission of toxic fumes and pollutants. They are the second highest contributor to the poor air quality of Delhi with 3182 industries.

4. Dust By Construction Pollution

Construction and dust pollution has been one of the major factors that led to this massive air pollution in Delhi. According to DPCC, 30 percent of the Pollution in Delhi has been due to the construction and demolition. This pollution is not much under attention and the government right now is taking steps to change that.

5. Fire in Bhalswa Landfills

Bhalswa Landfill is a dumping ground that has been in use since 1984. It spread about 52 acres and has reached to heights of 62 metres. It has been creating havoc in Delhi for years now. The landfill has been used beyond its capacity way before but still no waste management has been done. The waste that keeps lying around starts decomposing and because the volume of waste is so high that the whole area becomes prone to a fire. Because of the nature of the waste, the smoke from the fire not only produces a large amount of particulate matter, it also releases toxic amounts of Carbon Monoxide, Hydrogen Sulphide among the few. In 2019 also, an incident where a fire started that set the landfill and Jahangirpuri ablaze.

6. Colder Weather

Cold weather in Delhi has also managed to be a significant part of Delhi pollution. As the temperature dips in Delhi, it lowers the aversion height of all the smog and other particulate matters in the air. Aversion height is the altitude from ground towards the sky, till which the particulate matter can rise. During summers, the aversion height is much above and far from the ground so all the pollutants rise up and are not much harmful to us . But when the winters come, the aversion height drops, which leads to all the smog being a part of the air we inhale.

7. Stagnant Winds

With a huge amount of pollutants being dispersed in the Delhi air daily, stagnant winds can cause a problem. When these huge amounts of pollutants don’t get a good speed of the wind, they start accumulating at a place which causes a hazy smog and doesn’t let the pollutants spread out.

8. Geographic Location

Delhi is landlocked between the states of Haryana, Rajasthan and Uttar Pradesh which and Himalayas and due to this, the winds that can carry the pollutants is near to non-existent. The winds that come from the coastal region carry pollutants with them which get trapped by the Himalayas i.e. in Delhi. For example, Chennai’s vehicle density is 19 times more than Delhi’s but still Chennai has a moderate amount of particulate matter in its air because as its a coastal region and all its pollutants get carried away.

9. Population Growth

Population growth is the grass-root cause of air pollution. More people means more vehicles, more amenities, more industrial products, more agricultural practices. Delhi saw a stark population increase from 2011 to 2019. The population went from 16.7 million in 2011 to 20 million in 2019.

10. Not Enough Public Transportation

Even though Delhi boasts of managing the world’s biggest fleet of buses under it, this system needs to be bigger and better. Because as the public transport will be better and cheaper, then only there will be less vehicular emissions. Even though Delhi is 14 times bigger than Paris, Paris’s metro line is double the length of Delhi's.

11. Lack of Active monitoring

Earlier also, active monitoring wasn’t done which led to a sudden realization after years that pollutant levels in the air have shooted. Active monitoring could have helped know the rising patterns of the air pollution so that it could be curbed at its initial days.

12. Badarpur Thermal Power Plant

Badarpur Thermal Power Plant has been one of the major contributors to air pollution in Delhi in the past. But in 2015, it was seen that even though its share in electricity supply in Delhi was approximately 8 percent,but its share in the total number of particulate matters in Delhi was 80-90%.It was shut down in 2015 as a measure to reduce the number of air pollutants in the air.

History of Delhi Pollution: How has it been through the years?

1980s: The Start: Delhi started seeing a rise in the pollution levels in the 80’s where the emergence of vehicles started taking a toll on the air and stubble burning started in the states of Punjab and Haryana. At that time, riots were also on a high after Indira Gandhi got assassinated and banning burning of crops seemed like an anti-religion rule so all the state governments avoided rolling it out and thus the pollution started rising.

1996: The situation of the city worsened to which the Supreme Court ordered the Delhi Government to submit a plan on how they plan on reducing the rising Delhi air pollution.

1998: Increase in Diesel run vehicles peaked the amount of PM2.5 particles in the air.

2000: There was an enormous increase in a lot of pollution causing activities like construction, industrial manufacturing and vehicular emissions. From the 2000 to 2010, the level of PM10 particles in air went from moderate to poor levels. Vehicles also increased in the capital city of India with an annual growth rate of 10.75%.

2004: The National Air Quality Index was introduced seeing the air pollution scenario. Under the NAQI, air was categorized into six levels. good, satisfactory, moderate, poor, very poor and severe/hazardous to differentiate how polluted the air was.

2016: In October 2016, Delhi underwent a major smog episode, one of its first in line of the other that came through. Air Quality Index. As the Diwali season set in, the PM2.5 level in Delhi city reached approximately 750 μg/m3 to the horror of everyone. The AQI levels reached close to 13 times more than the permissible amount. This awoke Delhi and its officials and the government bodies to the devastating effects of air pollution. The whole city got covered with smog.

2017: The Great Smog of Delhi - The incident known as the great smog has been the most devastating phase Delhi had to go through in terms of air pollution. The PM2.5 and PM 10 levels, whose healthy limits are 60-100 μg/m3 rose to 999 μg/m3 which was the highest level the sensors could calculate. The same year in November 2017, on the second day of a test match between Sri-Lanka and India 2 players started vomiting due to the humongous amount of smog and pollutants in the air.

2018: PM2.5 concentrations increased and AQI level reached 400. The low visibility and respiratory problems increased.

2019: In November, a public health emergency was declared due to severe smog. School closures and restrictions on outdoor activities enforced. And AQI levels exceeded 500 in many areas because of stubble burning in neighboring states.

2020: COVID-19 lockdowns drastically reduce air pollution. However, a severe fire at the Bhalswa landfill site increased the AQI level. And by November AQI spiked to 435 “hazardous” categories.

2021: Fire broke out again at Ghazipur landfill in 2021 starting to worsen the air quality. And post-Diwali has increased the AQI level to 462 because of stubble burning mainly in Haryana and Punjab.

2022: The massive fire at Bhalswa landfill drew attention to the waste management and air pollution caused by it. Again the AQI level reached 302 in November due to many reasons.

2023: PM2.5 annual average level reached 100.9 (µg/m3) and increased 2% as compared to 2022. Periodical spikes were recorded in AQI levels, however, the air quality improved than in previous years. An Air quality report declared New Delhi as the most polluted capital city in the world.

2024: At the beginning of the year, AQI recorded worsen as crossed the 400 level. But for the first time in the last nine years, AQI in Delhi during February remains less than 200. Till April AQI remains at a better level. However, the heatwave and rising temperature increase the AQI to unhealthy to hazardous levels.

What are the effects of Delhi Air Pollution?

1. Health Problems in Delhi Due to Air Pollution

In Delhi, poor air quality has damaged the lungs of half of the children in Delhi, according to WHO. As PM2.5 is such a small particle it can easily enter one’s lungs and erode one’s respiratory wellness.Increased risks of cancer, epilepsy and diabetes has also been seen among the children.

PM2.5 and PM10 particles are the main causes of reduced lung capacity. This in turn leads to sore throat, cough, asthma, allergies and lung cancer. Excessive CO2 in the air leads to headache, fatigue and loss of productivity. The number of non-smokers in Delhi who suffered from lung cancer shot up from 10 percent to 50 percent in a decade, all due to the increased pollutants in the air that people have to breathe.

2018: Patients with asthma, bronchitis, and other respiratory ailments rise. The respiratory problems cases in hospital admissions increased by over 20% in comparison to the previous year.

2019: 15% increase in cases of respiratory infections and chronic obstructive pulmonary disease (COPD) patients.

2020: A 12% spike in pollution-related conditions in hospital visits because of respiratory illness and cardiovascular diseases. A report indicates over 50,000 deaths in India attributed to air pollution.

2021: A new study suggested the correlation between high pollution levels and mental health issues. Also, a 10% increase in patients with cardiac and respiratory issues because of air pollution.

2022: Reports calculated a 13% increase in asthma, bronchitis and other respiratory problems in hospitals.

2023: Chronic respiratory and cardiovascular conditions increase 10% as compared to previous year data.

2024: 200 cases of diabetes and heart disease due to air pollution in the first 2 months of the year. More patients with respiratory issues such as asthma, chronic obstructive pulmonary disease (COPD), bronchitis and cardiovascular diseases.

2. Smog in the air

Smog is exactly what the name might suggest, it is the mixture of smoke and fog. Excessive pollution in air causes smog and Delhi has had its fair share of smog over the years. Delhi observed the great smog in November 2017 which engulfed the whole city in it.

3. Environment change

The environment is constantly degrading with the increasing air pollution. The main effect of Delhi pollution in the environment is the depletion of the ozone layer in the atmosphere due to which the UV rays from the Sun can directly enter the earth. The emission from industries is also a big cause for the global warming that is leading the glaciers to melt at a really fast pace.

4. Economy

Thousands of crores have been spent by the Central Government and the Punjab and Haryana Government to stop the stubble burning and help with better ways to dispose of the waste. Delhi Government has also been getting Green funds to fight the Air Pollution and curb it.

Measures taken Up By the Government to control Delhi Pollution

1988: As advised by Environment Pollution (Prevention and Control) Authority (EPCA), the Court made a ruling that the buses in the city change from using Diesel to CNG.

2010: BS-IV based vehicles were said to be mandatory.

2014: Air Quality Index was launched by the Union Environment Ministry.

2016: Arvind Kejriwal’s Promises

• ● Delhi Schools to be shut while AQI levels are at hazardous levels.
• ● Construction and demolition work stopped for 5 days.
• ● Diesel generators asked to be shut for 10 days
• ● The Environment department was asked to make an applicationto monitor burning of the leaves in the city.
• ● Vacuum cleaning of roads will be done
• ● Water sprinkling will start at areas with high PM 10 levels
• ● People will be advised to stay at home
• ● Faster adoption and manufacturing of electric vehicles will be done
• ● Vehicles that are older than 15 years will be fined
• ● Smog towers will be installed at hot spots
• ● By 2021, Delhi metro will be powered 100% by solar energy.

2017: The ‘Odd-Even’ rule was imposed. Parking fees were imposed and increased but due to no proper system, this scheme failed. Crackers were banned.

2018: The Graded Response Action Plan (GRAP) initiated the air pollution combation because of severe episodes. As restrictions on construction activities, and increased monitoring.

2019: 2019: The government and GRAP again introduced an odd-even vehicle rationing scheme during peak pollution periods. Also, they promoted electric vehicles (EVs) to control air pollution.

2020: A 10 member air pollution team was made. Their work was to examine the complaints from Green Delhi Mobile Application and then work towards solving them. A little relief in air pollution thus public awareness campaigns have increased and firecrackers restrictions continue on Diwali.

2021: The Commission for Air Quality Management (CAQM) was formed to combat air pollution. Green cover increased in Delhi. All thermal (Coal) based power plants closed and gas-based plants were promoted. The first E-waste eco-park was built in Delhi and urged neighboring states to work together for air pollution.

2022: The government has increased the use of road cleaning machines that involve water guns etc. The first electric bus was launched to enhance public transportation and reduce natural gas emissions. Every vehicle older than 10-15 years banned because of emissions.

2023: Green War Room has been established for air pollution monitoring. Launched Green Delhi App for citizens to report against air pollution near them directly. PUSA bio-decomposer sprayed by the government on around 3,200 acres of farmland to manage stubble burning.

2024: Anti-smog guns and water sprinklers used for dust pollution reduction. Over 200 teams were tasked to monitor industrial and construction site pollution. PUCC (pollution under control certificates) enforcement ramped up and over 1,00,000 commuters were fined till May. Special teams deployed for pollution hotspots.

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How bad is the infamous Delhi Pollution

The residents of the capital city of India have to bear the brunt of the annual winter pollution. The air quality drops to such a level that the city is compared to a gas chamber! Delhi starts witnessing high levels of air pollution in late October and the contamination worsens until the end of the year. Many parts of the city experience pollution levels as high as 150 times the stipulated levels recommended by the World Health Organisation.

As a result of these events, the pollution levels are lesser in summers as compared to winters, provided the spatial and meteorological remain the same. You can observe a similar effect during winter afternoons. The increase in heat levels down pollution slightly.The early mornings and the nights are the worst. The impact of inversion is visibly evident, which is why the air quality plummets during these hours.

Why does Delhi air quality index deteriorate in winters?

Atmospheric inversion occurs in winters. The normal conditions reverse themselves, and air near the lower atmosphere is cooler and denser. The relatively warmer air of the upper layers, hence, acts as an atmospheric lid. This lid entraps the pollutants within the cold layer and evades their atmospheric dispersion. Therefore, the vertical mixing occurs in the lower layer itself.At constant emission rates and concentration of pollutants, the lesser the temperature, the more is the pollution.

As a result of these events, the pollution levels are lesser in summers as compared to winters, provided the spatial and meteorological remains the same. You can observe a similar effect during winter afternoons. The increase in heat levels down pollution slightly.The early mornings and the nights are the worst. The impact of inversion is visibly evident, which is why the air quality plummets during these hours.

However, one of the worst incidents happened during an international cricket test match between India and Sri Lanka in December 2017. The match was stopped because many Sri Lankan players became sick. Several players experienced breathing problems and vomited. The Indian Medical Association expressed their concern over the unfortunate incident and insisted ICC to adopt a policy on pollution.