VW’s current set of diesel engines - the 1.5-litre, 4-cylinder TDI and the 2.0-litre TDI are all BS4 compliant. The smaller 1.5-litre unit might face the axe post the implementation of BS6 norms in April 2020. Meanwhile, the bigger unit will be upgraded to meet the stricter emission norms. To replace the small diesel engine option, Volkswagen is expected to introduce CNG versions of the Polo, Ameo and Vento post April 2020. The German carmaker is not the only one to respond to consumer concern over the future of their diesel models in the BS6 era. Maruti also announced a 5-year/1 lakh km warranty for its diesel-powered cars which range from the Swift to the S-Cross, free of cost. However, its petrol-powered offerings are covered by a 2-year/40,000km warranty only.