The Union Ministry of Road Transport and Highways has allowed retro fitment ofcompressed natural gas (CNG) and Liquefied petroleum gas (LPG) kits in petrol and diesel vehicles that are compliant with the BS-VI emission norms.
Currently, such modifications are only permitted in BS-IV emission norms compliant vehicles.
The Ministry highlighted that Compressed natural gas (CNG) is an environment-friendly fuel and will reduce the emission levels of carbon monoxide, hydrocarbon, particulate matter and smoke as compared to petrol and diesel engines/
BS Norms
Bharat stage (BS) emission standards were adopted to regulate air pollutants from the internal combustion engines, and engine equipment, including motor vehicles.
The Bharat stage (BS) standards and the timeline for implementation are set by the Central Pollution Control Board under the Union Ministry of Environment, Forest and Climate Change.
All new vehicles manufactured have to be compliant with the regulations.
The Bharat Stage (BS) Standards are based on European regulations that were first introduced in India in 2000, and with time more strict standards were adopted.
With the introduction of the first Bharat Stage (BS-1) standards, the catalytic converter became mandatory for petrol vehicles and unleaded petrol was introduced in the Indian market.
In 2016 Indian government announced that it would skip the BS-V and adopt BS-VI norms by 2020.
The Supreme Court has banned the sale and registration of motor vehicles fitting with Bharat Stage IV emission standards in the entire country from 1 April 2020.
While the higher Standard norms help in bringing down pollution levels, they also increase vehicle costs due to the improved technology and higher fuel prices.
BS-VI Standards
BS-VI emission norms set the maximum permissible levels for pollutants that an automotive or a two-wheeler exhaust can emit.
Sulphur content in BS-IV fuel has five times lower (10ppm) as compared to sulphur content in BS-IV fuel (50ppm).
The nitrogen oxide emission level for diesel engines and petrol engines will decline by 70% and 25% with the BS-VI standards.
The introduction of Diesel Particulate Filter (DPF) and Selective Catalytic Reduction (SCR).