They now have a big inventory of BS-III vehicles, which will have to be upgraded or exported to countries where BS-III standards still prevail. The government, unfortunately, did not clearly state the position in time. The adoption of BS-IV standards is expected to make a difference to air pollution in the country. Emissions from BS-IV compliant trucks are 80% less than those from BS-III vehicles. Particulate emissions will be halved in the case of cars. The benefits of shifting to stricter emission standards are clear from this. Air pollution is a serious problem and vehicular emissions are a major cause of pollution. BS-IV standards were implemented in some cities a few years ago. One reason for the failure to implement them in the entire country was that refineries could not produce the fuel that meets BS-IV norms in adequate measure. BS-IV compliant fuel is now available all over the country, after an investment of about Rs 30,000 crore by refineries.

The present plan is to bring the BS-VI norms into force in 2020 after skipping the BS-V stage. Refineries may have to invest another Rs 50,000 crore to upgrade to BS-VI standards which are to be implemented by April 2020. Vehicle manufactures, too, will have to go in for the required technology upgradation by then. They will also have to make huge investments. But the social, economic and health returns will be much more than the investments. There was some shifting of deadlines at the time of transition from BS-II to BS-III norms, which may have encouraged the auto companies to assume that the BS-IV date was also flexible. The government must ensure that a similar confusion and uncertainty will not arise at the time of the next transition.