The government will today issue showcause notice to global car manufacturer Volkswagen, after a government testing agency found significant variations in the emission levels of the firm's three diesel models. Additional Secretary in the Heavy Industries Ministry Ambuj Sharma told this to PTI. This, after the Automotive Research Association of India found that three on-road models had showed a variation in their emission levels when compared to the data provided by the company during laboratory tests.The three on-road models are Jetta, Audi A4 and Vento.<br/><br/>Volkswagon has admitted that 11 million diesel engine cars<br/>worldwide were fitted with the software that helped in manipulating emission tests. It faces fine of up to 18 billion dollar in the US.<br/>Meanwile, Volkswagen said in Berlin today that it had uncovered inconsistencies when determining carbon dioxide emission levels which could affect around eight lakh cars globally. Company's top management will immediately start a dialogue with responsible authorities regarding the consequences of these findings, the carmaker said.