Delhi Chief Minister Arvind Kejriwal on Monday sought Prime Minister Narendra Modi's cooperation to implement the odd-even formula intended at reducing the number of vehicles on Delhi's roads.In a letter to Modi, Kejriwal urged the prime minister to tell all his ministers and secretaries in the ministries to help implement the radical step, aimed at battling rising pollution in the capital."I request you to motivate your ministers and secretaries to follow this plan. This will send a good message to the people and also encourage our efforts in this connection," he said.He said the implementation of the proposed plan between January 1 and 15 will benefit if the prime minister issued the necessary direction or appeal.The Delhi government earlier this month decided to introduce a formula, according to which private vehicles bearing odd and even registration numbers as the last digit will be allowed to ply on alternate days from the first day of the New Year.Kejriwal said the odd-even formula would not apply on auto-taxis, public transport and emergency vehicles like ambulances."Me and my colleagues will strictly follow this formula and will opt for car-pooling for commuting. We will repeat this plan if we get favourable results out of this," Kejriwal wrote.