The National Green Tribunal (NGT), despite its apprehensions, gave its nod to the odd-even scheme. The formula will be implemented in Delhi-NCR whenever PM 10 crosses 500 and PM 2.5 cross 300. The tribunal, while giving the green signal to the odd-even scheme, questioned the city government as to why it was granting exemptions to certain sections if the aim was to improve air quality. NGT observed that its patience shouldn't be tested, asking the Delhi government that when the statistics have indicated that rain leads to a fall in pollution levels, why wasn't action taken? It's now being taken after the Tribunal said so.