Environment, GS-3, Uncategorized

Air Pollution Indexes, Standards, Reports and Fly Ash

National Ambient Air Quality Standards (NAAQS)

  • Air (Prevention and Control of Pollution) Act empowers Central Pollution Control Board to set standards for the quality of air.
  • Current NAAQS were notified by CPCB in the year 2009.
  • Pollutants  covered under NAAQS are
  1. Sulphur Dioxide (SO2),
  2. Nitrogen Dioxide (NO2),
  3. Particulate Matter PM 10,
  4. Particulate Matter PM 2.5,
  5. Ozone (O3),
  6. Lead (Pb),
  7. Carbon Monoxide (CO),
  8. Ammonia (NH3),
  9. Benzene (C6H6),
  10. Benzo(a)Pyrene (BaP),
  11. Arsenic(As),
  12. Nickel (Ni).

National Air Quality Index

  • NAQI, launched by CPCB,  is a number used to communicate to the public how polluted the air currently is or how polluted it is forecasted to become.
  • The classifications of air quality are part of a 6 grade, colour coded taking into account 8 pollutant levels.
  • These pollutants are:

1. Ground-level Ozone or O3

2. Particulate Matter (soot and dust) – PM 2.5 and PM 10

3. Carbon Monoxide or CO

4. Sulphur Dioxide or SO2 and

5. Nitrogen Dioxide or NO2

6. Ammonia or NH3


The programme will not be notified under the Environment Protection Act or any other Act to create a firm mandate with a strong legal back up for cities and regions to implement NCAP in a time bound manner for effective reduction.

Key features of the National Clean Air Programme (NCAP):

Achieve a national-level target of 20-30% reduction of PM2.5 and PM10 concentration by between 2017 and 2024.

Central Pollution Control Board (CPCB) will execute this nation-wide programme in consonance with the section 162 (b) of the Air (Prevention and Control of Pollution) Act, 1986.

The plan includes 102 non-attainment cities, across 23 states and Union territories, which were identified by Central Pollution Control Board (CPCB) on the basis of their ambient air quality data between 2011 and 2015.

Non-attainment cities are those which have been consistently showing poorer air quality than the National Ambient Air Quality Standards. These include Delhi, Varanasi, Bhopal, Kolkata, Noida, Muzaffarpur, and Mumbai.

The plan proposes a three-tier system, including real-time physical data collection, data archiving, and an action trigger system in all 102 cities, besides extensive plantation plans, research on clean-technologies, landscaping of major arterial roads, and stringent industrial standards.

It also proposes state-level plans of e-mobility in the two-wheeler sector, rapid augmentation of charging infrastructure, stringent implementation of BS-VI norms, boosting public transportation system, and adoption of third-party audits for polluting industries.

Benefits of the programme:

NCAP has certainly helped kick start the much-awaited good practice of setting air pollution reduction targets. The biggest advantage of such targets is that it helps decide the level of stringency of local and regional action needed for the plans to be effective enough to meet the reduction targets.

Need of the hour:

The MoEF&CC, as a nodal central and apex agency, will have to flex its authority to ensure all NCAP indicators are integrated with multi-sector and inter-ministerial programmes to align with the air quality target and objectives.

NCAP should not become only a top-down prescriptive approach. In fact, within the federal structure, NCAP, while ensuring compliance, will also have to create enough room for tighter action that can be even stronger than the common minimum national programme as defined by NCAP.

State governments and city authorities should be encouraged and enabled to take those extra steps to meet local targets. City-wise air quality targets will clearly show where much deeper cuts will be needed for hotspot and stronger regional action.

NCAP will also have to join all critical dots with clarity. For instance, in case of vehicular pollution, the main body of the plan has ignored mobility, transportation and urban planning strategies, though fortunately, the indicative broadsheet of action at the end has listed public transport, transit-oriented development policies, and non-motorised transport. But these will have to be detailed out with clear pathways and milestones and integrated well with the NCAP strategies.


Context: IQAir AirVisual and Greenpeace have released World Air Quality Report 2018.

  • The main objective behind the report was to measure the presence of fine particulate matter known as Particulate Matter (PM) 2.5, which has been recorded in real-time in 2018.

Highlights of the report:

  • The report, based on a study of 3000 cities, said that 64 percent of the cities exceeded the World Health Organisation’s annual exposure guideline for PM 2.5. In South Asia itself, 99 percent of the cities exceeded the WHO’s safe standard exposure of 10 micrograms/cubic metre annually.
  • Of the 10 cities with highest pollution, seven are in India, while one is in China and two are in Pakistan.
  • India’s Gurugram led the list of most polluted cities in the world in 2018, followed by Ghaziabad, Faridabad, Noida, and Bhiwadi in the top six worst-affected cities.
  • Delhi was ranked at number 11 on the pollution chart.
  • Among the top 30 most polluted cities, India makes up for 22 with five in China, two in Pakistan and one in Bangladesh.
  • The only non-Indian city in the top five list is Faisalabad, Pakistan.
  • Delhi was ranked as the most polluted capital in the world, with Dhaka at second and Kabul at third position.
  • China made a remarkable improvement since 2013 as the country’s pollution levels have gone down by 40 percent. In 2013, Beijing topped the pollution charts. Beijing ranks now as the 122nd most polluted city in the world in 2018.
  • In South Asia, out of 20 most polluted cities in the world, 18 are in India, Pakistan and Bangladesh.
  • In Southeast Asia, Jakarta and Hanoi are the most polluted cities.

Measures to improve air quality:

As suggested by Greenpeace, following measures can be employed to fight air pollution in the country:

  • Improving public transport.
  • Limiting the number of polluting vehicles on the road.
  • Introducing less polluting fuel (Bharat VI).
  • Strict emission regulations.
  • Improved efficiency for thermal power plants and industries.
  • Moving from diesel generators to rooftop solar.
  • Increased use of clean renewable energy.
  • Electric vehicles.
  • Removing dust from roads.
  • Regulating construction activities.
  • Stopping biomass burning, etc.


Fly ash

  • Fly ash is ejected mostly by thermal power plants as by-products of coal burning operations.
  • Fly ash pollutes air and water and may cause heavy metal pollution in water bodies.
  • Fly ash affects crops and vegetation as a result of its direct deposition on leaf surfaces.
  • Fly ash particles are oxide rich and consist of silica, alumina, oxides of iron, calcium, and magnesium and toxic heavy metals like lead, arsenic, cobalt, and copper.
  • Major oxides are present are aluminium silicate (in large amounts), silicon dioxide (SiO2) and calcium oxide (CaO).
  • Cement can be replaced by fly ash up to 35%, thus reducing the cost of construction, making roads, etc.
  • Fly ash bricks are light in weight and offer high strength and durability.
  • Fly ash is a better fill material for road embankments and in concrete roads.
  • Fly ash can be used in the reclamation of wastelands.
  • Abandoned mines can be filled up with fly ash.
  • Fly ash can increase crop yield when added to the soil. But if it gets deposited on the leaf, it will reduce photosynthesis.
  • It also enhances the water holding capacity of the land.

Q. With reference to ‘fly ash’ produced by the power plants using the coal as fuel, which of the following statements is/are correct?

  1. Fly ash can be used in the production of bricks for building construction
  2. Fly ash can be used as a replacement for some of the Portland cement contents of concrete
  3. Fly ash is made up of silicon dioxide and calcium oxide only and does not contain any toxic elements.

Select the correct answer using the code given below

  1. 1 and 2
  2. 2 only
  3. 1 and 3
  4. 3 only
  • Fly ash does contain heavy toxic elements like arsenic, cobalt, lead etc.

Answer: a) 1 and 2

Thank you!

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