What Car? Q&A - Which cars can escape the C-charge?
A: When the revised congestion charge levels come into play on October 27, there will be three charges: free, £8 and £25.
You may think that the charge means sacrificing style, but this isn't the case - some BMW 1 Series and Audi A3 models fit into the lowest bracket.
Cars that are exempt from the charge must emit 120g/km of carbon dioxide or less and fit into Vehicle Excise Duty (VED) bands A and B.
Cars that emit more than 225g/km, or which are in VED band G, or cars registered before March 2001 with engines over 3.0 litres, will be liable for the full £25 charge.
Any other cars pay the current £8 charge. At the moment, 17% of cars driving into London would pay the maximum £25 charge, with only 2% getting into the city for free. The rest pay the current £8 charge.
Electric, hybrid, and some LPG cars registered before October 27 this year will remain exempt from the congestion charge until January 2010, as well as disabled blue-badge holders.
Drivers of cars exempt from the charge do, however, have to register with Transport for London and pay an annual £10 registration fee.
To see which cars are greenest by category, click here.