What are BS norms?
Bharat Stage emission standards, introduced in 2000, are emission standards that have been set up the Central government to regulate the output of air pollutants from internal combustion engine equipment, including motor vehicles. The different norms are brought into force in accordance with the timeline and standards set up by the Central Pollution Control Board which comes under the Ministry of Environment and Forests and Climate Change.
The Bharat Stage norms are based on European regulations. In 13 major cities, Bharat Stage IV emission standards were put in place in April 2010. BS-IV norms were supposed to come into effect nationwide from April 2017.
Difference in BS-IV and BS-VI standards
The BS norms have been similar to Euro norms till now, and with norms after BS-IV not defined yet, we compare the existing BS-III and BS-IV norms in India with the Euro 6 norms on which India’s emission norms have been set.
Petrol Emission Norms (All figures in g/km)
| Emission Norm | CO | HC | NOx | HC+NOx | PM |
| BS-III | 2.30 | 0.20 | 0.15 | — | — |
| BS-IV | 1.00 | 0.10 | 0.08 | — | — |
| Euro 6 | 1.00 | 0.10 | 0.06 | — | 0.005 |
Diesel Emission Norms (All figures in g/km)
| Emission Norm | CO | HC | NOx | HC+NOx | PM |
| BS-III | 0.64 | — | 0.50 | 0.56 | 0.05 |
| BS-IV | 0.50 | — | 0.25 | 0.30 | 0.025 |
| Euro 6 | 0.50 | — | 0.06 | 0.17 | 0.005 |
Source – Indian Emissions Regulations/ARAI
CO emissions and Carbon Monoxide emissions are more evident in Petrol engines. Long Term exposure can prevent oxygen transfer and increase headaches/nausea.
HC emissions are Hydrocarbons which are again more prevalent in Petrol engines. Short term exposure can cause headaches, vomiting and disorientation.
NOx emissions are Nitrogen Oxide emissions which are more prevalent in Diesel engines. Long Term exposure can cause Nose and eye irritation and damage lung tissue.
PM is Particulate matter, again more prevalent in a Diesel engine. Long Term exposure can harm the respiratory tract and reduce lung function.
The parameters determining emission from vehicles :
- Vehicular Technology
- Fuel Quality
- Inspection & Maintenance of In-Use Vehicles
- Road and Traffic Management
Each one of the four factors mentioned above have direct environmental implications. The vehicle and fuel systems have to be addressed as a whole to meet the emission standards.
History of Emission Norms in India
The contribution of vehicles to pollution is known and there is need to reduce vehicular emissions on a continuous basis. Indian Automotive Industry recognizes the fact and has worked continuously for control of emissions as per the Auto Fuel Policy .It proactively developed environment-friendly technologies. India today has some of the most fuel efficient vehicles in the world.
The first stage of mass emission norms came into force for petrol vehicles in 1991 and in 1992 for diesel vehicles.
From April 1995 mandatory fitment of catalytic converters in new petrol passenger cars sold in the four metros of Delhi, Calcutta, Mumbai and Chennai along with supply of Unleaded Petrol (ULP) was affected. Availability of ULP was further extended to 42 major cities and now it is available throughout the country.
In the year 2000 passenger cars and commercial vehicles met Euro I equivalent India 2000 norms, while two wheelers were meeting one of the tightest emission norms in the world.
Euro II equivalent Bharat Stage II norms are in force from 2001 in 4 metros of Delhi, Mumbai, Chennai and Kolkata.
The first Auto Fuel Policy was announced in August 2002 laying down the Emission and Fuel Roadmap upto 2010.As per the same the 4 wheelers moved to Bharat Satge III emission norms in the 13 metro cities from April 2005 and rest of the country to Bharat Stage II.
Bharat Stage IV for 13 Metro cities was inplemented from April 2010 and the rest of the country moved to Bharat Satege III. Bharat stage IV has been further extended to additonal 20 cities from October 2014.
The 2nd Auto Fuel policy 2025 was submitted to the Minstry of Petroleum & Natural Gas (MoP&NG) whiich had constituted the same in May 2014 and is hosted on the MoP&NG website. The same lays down the Emission and fuel road map upto 2025.
The proposed road map envisages BS IV across the country by 2017 in a phased manner and BS V emissions in 2010/2021 and BS VI from 2024. The same has still to be accepted by the Government and notified.
Since India embarked on a formal emission control regime only in 1991, there is a gap in implementing in comparison to Europe. This has helped the technologies to mature and facilitate Indian industry to meet the regulations at an affordable cost for the Indian consumers.
