Pressure from British BMW buyers has forced the company to adapt its diesel-powered X5 4x4s so that they emit less than 225g/km of carbon dioxide, and don’t get stung by the Mayor of London’s modified congestion charge. The vehicles are a direct response to proposed changes to London’s Congestion Charge which will saddle cars emitting over 225g/km to the tune of £25 a day. Deliveries of the modified 3.0d and 3.0sd X5s will begin in December. The 232bhp 3.0d will now achieve CO2 emissions of 214g/km, down from 231g/km, while the more powerful 282bhp 3.0sd will drop to 216g/km. The cars will also be cheaper for company car tax payers all over the UK.The improvements, which have been specifically developed for the UK market, have been achieved by fitting a regenerative braking system, an intelligent alternator (it mainly operates when the engine is decelerating, saving fuel) and intelligent airflaps behind the radiator grille that improve the car’s aerodynamics at speed – features that have recently appeared on other BMWs as part of its Efficient Dynamics programme.The revisions will make these two models, and the hybrid Lexus RX400h and Volvo’s XC90 D5 the only large, premium-brand four-wheel drives that do not attract the proposed £25 charge.The company is also working to improve its 318d 3-series, which currently emits 122g/km, to get it below the 120g/km threshold that Transport for London has said will be exempt from any charge next February.