Bloomberg: London Mayor Boris Johnson began a review of the traffic-congestion zone that may lead to the program being scrapped in the city’s western districts. Drivers pay 8 pounds ($14) a day to enter an area that covers most of central and west London. The central zone was introduced in 2003 and extended west last year to the districts of Kensington & Chelsea, Notting Hill and Knightsbridge, drawing objections from some residents. The city is seeking comments from west London …