The National Green Tribunal (NGT) on Friday said the odd-even vehicle rationing scheme won't be allowed in the capital till its efficacy was known.

The green court issued the directive a day after the Delhi government announced it would bring back the odd-even plan from November 13 to 17 to combat severe air pollution in Delhi and NCR region.

The tribunal said the government needed to satisfy the court that the odd-even car rationing scheme was productive.

NGT chairperson Swatanter Kumar said while the green bench was not against the odd-even scheme, it wanted to know how it helps.

"We will not allow odd-even vehicle rationalisation scheme until you prove that it's not counter-productive," he said.

"Reports from DPCC (Delhi Pollution Control Committee) and CPCB (Central Pollution Control Board) showed there was no change in pollution level last time. It's clear that small cars are not major polluters; it's the diesel and overloaded vehicles," he said.

The bench also asked the government to clarify how many out of the proposed 500 extra buses to boost public transport during the odd-even vehicle rationing scheme would be running on diesel.

Kumar observed that even Delhi Metro failed to help during the last edition of odd-even as during peak hours "it was difficult to even breathe inside the metro".

He also asked the government to clarify the logic behind allowing two-wheelers.