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Q) Which of the statement is correct regarding the Bharat Stage Norms?
1) BS VI also reduces the particulate Matter (PM) limit by 80% from BS IV for diesel vehicles
2)Onboard Diagnostics (OD) has been made mandatory for all vehicles
Which of the above statements is/are correct?

  1. 1 only
  2. 2 only
  3. Both 1 and 2
  4. Neither 1 nor 2


BS-VI Vehicle

  • Amid the COVID-19 pandemic, Supreme Court (SC) had extended the March 31, 2020 deadline for the sale and registration of BS-IV emission norm compliant vehicles.

Evolution of emission norms

  • The first stage of mass emission norms came into force for petrol vehicles in 1991 and in 1992 for diesel vehicles.
  • In 2000, passenger cars and commercial vehicles were met Euro I equivalent India 2000 norms (Bharat Stage).
  • Bharat Stage Norms are the standards set up by Central Pollution Control Board (CPCB)to regulate the output of air pollutants from internal combustion engines and spark-ignition engine equipment, including motor vehicles.
  • The exhaust gases now covered under the norms are: Carbon monoxide, Hydrocarbons, oxides of nitrogen (NOx) and Particulate matter.
  • These norms are based on the European standards.
  • Due to drastic rise in air pollution specially in Delhi and other parts of North India, India in 2016 decided to skip the BS-V norms altogether and adopt BS-VI norms by 2020.
  • Further in 2018, SC had ruled that no BS-IV vehicle would be sold or registered in India from April 1, 2020.

Difference between BS-IV and BS-VI

  • Nitrogen oxide level for BS VI-grade diesel engines and petrol engines will be brought down by 70% and 25%, respectively.
  • BS VI also reduces the particulate Matter (PM) limit by 80% from BS IV for diesel vehicles and introduces PM limit for petrol vehicles.
  • The Sulphur traces in BS VI fuel is five times lower (10 ppm) as compared to Sulphur traces in BS IV fuel (50 ppm), which is a reduction of 80%.
  • Onboard Diagnostics (OD) has been made mandatory for all vehicles which will give the vehicle owner or repair technician access to the status of the various

More about BS VI

  • Diesel Particulate Filter (DPF) and Selective Catalytic Reduction (SCR) are being introduced with the roll-out of BS VI norms, which were not a part of BS IV.
  • SCR converts NO and NO2 to molecular nitrogen and oxygen by reacting the NOx with ammonia in the presence of a catalyst. It thus reduces the harmful NOx emission.
  • Real Driving Emission (RDE) will be introduced in India for the first time with the implementation of Bharat Stage VI emission norms.
  • It will measure a vehicle’s emission in realtimeconditions against laboratory conditions.

Q) Which of the statement is correct regarding the Black Carbon?
1) It is said to be the largest contributor to climate change.
2)It is short-lived and remains in the atmosphere only for days to weeks
Which of the above statements is/are correct?

  1. 1 only
  2. 2 only
  3. Both 1 and 2
  4. Neither 1 nor 2




  • Study conducted on black carbon (BC) concentration near Gangotri Glacier revealed that BC concentration in the region increased by 400 times during summer.

More about news

  • This is due to emissions resulting from agriculture burning (in western part of the country), forest fires (along the Himalayan slopes) in summer and long-range transport of pollutants in winter.
  • This concentration accelerates melting of glaciers in the Himalayas and Tibet.
  • Himalaya-Hindu-Kush and Tibetan Plateau, which are collectively referred to as the Third Pole (TP), contain the largest ice mass on the planet outside of the polar regions.

Gangotri Glacier

  • It is thelargest glacier in Uttarakhandand is one of thesources of Ganges(Bhagirathi).
  • It originates at the northern slope ofChaukhambarangeof peaks inGarhwal Himalayas.
  • Gangotri is acombination of several other glaciers.

Black Carbon

  • It is a solid particle or aerosol(and not a gas). It results from incomplete combustion of fossil fuels and biomass. They absorb light and about a million times more energy than CO2.
  • It is said to be second largest contributor to climate change after CO2. It is short-lived and remains in the atmosphere only for days to weeks, before it descends as rain or snow.
  • When it falls to earth, it darkens the surface of snow and ice, reducing their albedo (the reflecting power of a surface), warming the snow and hastening melting.




  • A new study conducted by the University of Manchester, UK and Mahavir Cancer Institute and Research Centre, Patna has found uranium contaminating the groundwater in 10 districts of Bihar.

More about news

  • This is the first time that uranium content has been detected in groundwater in Bihar.
  • Uranium concentrations are elevated mostly in the North West-South East band along and to the east of Gandakriver and running south of the Ganga river towards Jharkhand

Uranium Contamination in India

  • The permissible limit according to the World Health Organization (WHO) is 30 microgram per litre.
  • However, unlike the limits for arsenic and other toxic or heavy metals specified in the Bureau of Indian Standards’ Drinking Water Specifications, there is no limit maintained for uranium.
  • Uranium can cause serious ailments such as thyroid cancer, chronic kidneys disease, blood cancer, depression and other serious ailments.


Sources of Uranium contamination

  • The source of uranium is naturally occurring, but human activities like over pumping enhance the uranium problem.
  • In many parts of India, aquifers are composed of sediment carried down from the Himalayas by streams or from uranium-rich granitic rocks
  • Overuse of these aquifers for human use reduces the water level and creates oxidisingconditions, which enhance the uranium’s solubility in water.
  • Interaction of the uranium with other chemicals in the groundwater, such as bicarbonate, can further enhance its solubility.

Solution: Ex situ Treatment

  • Ex situ Treatment of radioactive contaminants in ground water such as:
  • Adsorption or ion exchange: The water soluble contaminants are captured by sorption (absorption and adsorption considered as a single process) onto a solid support that can be natural or synthetic material.
  • Precipitation: This is mostly practiced above ground and involves addition of alkali to raise the pH & precipitate the oxide or hydroxide.

Solution: In-Situ

  • Remedial strategies based on in-situ chemical stabilization such as:
  • Redox Technologies: These technologies attempt to manipulate oxidation reduction conditions of the subsurface to reduce uranium to uranous(uranium IV) forms.
  • Flushing Technologies: This group of remediation technologies uses a variety of leaching solutions to dissolve solid-phase uranium and hydraulic extraction techniques to remove the solubilized uranium.



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