Bharat Stage (BS) is the emission standard stipulated by Indian regulatory bodies in tune with the directions of the Government of India. The regulations are formulated with a view to reducing emission of air pollutants from motor vehicles that use combustion or spark ignition engines. BS IV stands for Bharat Stage 4, the emission standards stipulated in the country for all kinds of vehicles registered on or after 1 April, 2017 till further enhancement in standards. As the number associated to BS increases, the standards become stricter and difficult to meet.
The BS stipulations are made in tune with the European emission norms which are denoted Euro 4, Euro 6 etc. Auto makers design the models and technology ensuring that the emissions by their vehicles are well within the stipulated ceilings. The stipulations are meant to check the ever increasing air pollution. However, the improved standards cause the cost of the vehicle to increase.
As per the recent order of the Supreme Court of India, the highest court of the country, new vehicles not complying with BS IV standards would not be allowed to register in the country. BS standards are almost equivalent to European norms and it may be noted that many foreign countries have already switched over to Euro 6. Hence the aim of Indian regulators is to implement BS VI by the year 2020 by skipping BS V. This will make India on par with developed countries in emission stipulations and will help to check pollution by vehicles.
The BS standards and the timeline for implementation are decided by the Central Pollution Control Board under the Ministry of Environment & Forests and climate change. India introduced the stipulations based on European standards first in the year 2000. BS III norms have been in force since October 2010 which is being replaced by BS IV from 1 April, 2017. BS IV stipulations have been in force in 13 major cities from April 2010. Since developed countries have already implemented stricter emission norms, India plans to implement BS VI by the year 2020.