The NGT on Friday asked the Delhi government to prove whether Odd-Even scheme reduced pollution levels in the city or else it would stay the imposition of the scheme. On the third day of the hearing, the tribunal said, "When the situation is improving, the government is trying to implement it. You should have done this earlier if you wanted to. Odd-Even will now cause inconvenience to people.” Under the Odd-Even formula, vehicles with the registration number ending with an even number are allowed on roads on an even date while those ending with an odd number are allowed on odd dates. The formula was first implemented for 15 days in January, 2016, and again in April, 2016. A study showed that Delhi's odd-even scheme had little impact on air. Delhi government is under fire from the NGT for failing to control air pollution in the city.