Emission norms, weight, engine size, passenger capacity and so on may be important guidelines for a public transport vehicle. But for the West Bengal government, colour appears to be of equal importance. Or, to be precise, any colour so long as it's blue and white, Chief Minister Mamata Banerjee's favourite colours. The Calcutta High Court had recently asked the state government to allow registered three-wheeler e-rickshaws to ply on Kolkata's roads. Accordingly, the Kolkata Municipal Corporation framed guidelines for the vehicles - and the mandatory blue-and-white colour scheme is one of them. Asked about this, an officer of the transport department, said since most of the new taxis and buses were also painted blue and white, e-rickshaws have been asked to do the same in the interests of uniformity.