"One week is a very short time. We want to continue the scheme till January 15 so that we get sufficient data from the exercise, as well as sufficient experience. This experience will help us finalise the car policy for Delhi," he said.

Earlier in the day, the HC had raised questions over the lack of adequate public transport in Delhi and the "inconvenience" it was causing the people because of the odd-even rule. Acknowledging the problem of public transport, Rai, however, claimed that in the past few days, neither the Delhi Metro nor buses had run to capacity, leaving scope for more commuters to use the public transport services.

"I have personally visited the Delhi Metro, which has capacity to ferry more people than it is doing now," Rai said, adding that with the addition of extra buses, DTC can carry 64 lakh passengers, which has not happened so far.

"We will submit a full report to the court on January 8, answering all the questions that have been raised," said Rai. He said the biggest benefit of the odd-even scheme has been decongestion, which has even improved the frequency of buses. "We have tried to make adequate arrangements and people have supported the initiative, including the chief justice of India," added Rai.

The minister also cited data collected by DPCC to illustrate the benefits of the odd-even scheme. "We will submit all the data related to pollution levels, which have shown a positive trend. Central Delhi has seen a declining trend of PM 2.5 levels by 33%," said Rai. He explained that the pollution levels were being measured in two categories, PM 2.5, which is caused primarily by transport emissions, and PM 10, caused by construction waste and dust.

"PM 10 hasn't seen much of a difference. The biggest source of this is construction dust, for which the Delhi government has already announced that by April, vacuum cleaners will be put in place," said Rai. He added, "PM 2.5 is between 200 and 300 g/m³ in central parts of Delhi, that is, a decrease of 33%. This is despite the negative weather conditions." But Rai did not elaborate on what is this 33% reduction against leaving some questions unanswered.

Some experts haven't seen any declining trend in air pollution levels in the data provided by CPCB or System of Air Quality and Weather Forecasting Research (SAFAR). But DPCC scientists compared the PM 2.5 and PM 10 levels for January 4 and 5 this year with same days of 2014.

"It had rained heavily last year so we are not comparing with 2015 levels, but this year levels have definitely reduced as per our records. For example, PM 2.5 average on January 4, 2014 was 409 micrograms per cubic metres compared to 370. This data is from our permanent monitoring stations," a scientist said. The traffic police on Wednesday challaned 130 cars for violating the odd-even rule, while transport department challaned 71 cars and 321 autos for various violations. The revenue department challaned 557 vehicles.