"You (Centre) say that every kind of fuel causes some or the other kind of pollution. Then by your logic either every type of vehicle should be banned, or everything should be allowed. What is the solution?" a bench headed by NGT Chairperson Justice Swatanter Kumar said.
The government told the green panel there was no proof that diesel vehicles which were over 10 years old were the sole cause of air pollution and all forms of fuel including CNG and petrol cause pollution in different capacities.
Additional Solicitor General Pinky Anand, appearing for the Ministry of Road Transport and Highways, told the green panel that according to an IIT Kanpur study vehicular emissions contribute only 20 per cent to the air pollution and out of this contribution of diesel vehicles is only 0.22 per cent.
The ASG told the top environment watchdog that while petrol emits carbon dioxide, CNG too causes pollution as it is high on nitrogen oxides.
Ms Anand said that the ministry has initiated several schemes and it is actively considering to implement scrapping policy and providing incentives to those who opt to condemn their old vehicles.
The bench then said, "You had stated before us that you were in favour of removing 15-year-old diesel vehicles. Today, you are saying something different. Have you ever measured emission from a single moving commercial or domestic vehicle."
To this, the ASG replied that all her arguments were backed by scientific studies and the government was for strict checking of pollution under control (PUC) norms. The hearing remained inconclusive and will continue tomorrow.
On January 13, the Centre had moved the Supreme Court seeking lifting of the ban on 10-year-old diesel vehicles in Delhi and NCR, saying it was affecting the economically weaker sections.
Noting that diesel is the prime source of air pollution in Delhi, the tribunal had held on November 26, 2014 that all diesel vehicles which are more than 10 years old, will not be permitted to ply in Delhi-NCR.