Delhi transport department officials have booked over 450 motorists for driving without a valid pollution under control (PUC) certificate. The prosecutions have been made under the fortnight-long drive launched on New Year's day. Of the 1,242 vehicles checked on the first day, 218 were found to be running without a valid PUC certificate. On Friday, 1,336 vehicles were checked. The number of motorists challaned till the evening were 210.