The maximum amount will be applied for those cars with CO2 emissions that exceed 225 g/km, as well as those registered before March 2001 with engines larger than 3 liters. Transport for London (TfL) estimates that up to 30,000 vehicles that fall under this new category are driven in London on a daily basis. TfL also believes that two-thirds of them won't be driven anymore under the new rules. "Nobody needs to damage the environment by driving a gas-guzzling Chelsea tractor in central London," Mr. Livingstone said.
Cars that emit fewer than 120g/km will get a 100-percent discount (as Toyota announced for its Aygo, Prius and Yaris recently and discussed in regards to EVs)
[Source: BBC News]