Let’s start with the history because the history of BSES becomes important if you wanna know why car companies keep updating their vehicle emission standards. In late 2000 the first ever emission norm standards was introduced with the name as BHARAT 2000 and these norms are only applied in 4 major cities which are Delhi, Mumbai, Chennai, Kolkata. But in 2006 the first Bharat Standard was introduced named BS2 and it applies in Nationwide because there are a lot of car manufacturer companies in India. And the Govt has to take some strict actions against the Pollution and harmful gases which can lead to many harmful diseases. But the government didn’t stop and they also introduced BS3 norms in 2005 for four wheeler vehicles all over the nation. And in 2010 BS4 emission standard was introduced for all types of vehicles around the country because of heavy pollution in the environment. But the thing which takes 5 years to fully implement the BS4 norms is the fuel. Look the fuel has to be different also and Big companies like Bharat Petroleum, Indian oil, they need time to upgrade their because BS4 norms applied all over the world but a BS4 engine has some sort different nature and that makes Fuel Industry to upgrade their Fuel to Fulfil the Requirement and in year 2017, BS4 becomes mandatory for every car manufacturer, 
if their products didn’t match the BS4 norms then govt will not launch their car in Indian market. And after BS4 the plan is to introduce and implement the BS5 norms but as we know Bharat Emission standard rely on Euro and Euro 6 was introduced and implemented in 2016 in European countries and that’s why the government introduced BS6. Because of heavy pollution in Delhi, Govt has to skip the BS5 norms and the only reason for skipping the BS5 is to apply the latest norms to reduce Pollution. Now let’s get on BSES because that’s why you clicked on this and the reason is from 2000 to 2022 the harmful gases percentage becomes low every year and this graph can help you a lot to understand why this is important.
Like you see in the graph the graph is going down every year and that’s why BS6 norms are important for humans as well as for a healthy environment to live in. One more major thing on which the government has taken strict action is vehicle age. If your vehicle is petrol powered then its age limit for road legal will be 10 years and if you have a Diesel engine powered vehicle then you can drive it on road for 10 years. And that rule will help in reducing pollution as well as it will reduce the number of old vehicles which produce more pollution and harmful gases.
