Yes, London should look into banning cars. Although the congestion charges initially helped to reduce pollution, the levels being currently seen show that more needs to be done. Both Delhi and Paris have experienced success by banning half of the number of cars each day, and London officials should try to find a similar solution.
Even though pollution is a big problem in London, there still need to be cars. There are people who have disabilities. It is not easy for these people to use the old subway systems. London should allow these people to use cars. It's the only fair way to allow them to participate in the workforce.
London can successfully decrease pollution in the city without completely banning cars by doing what some other large cities have done. Stricter emissions requirements could decrease air pollution, and incentives for using public transportation could decrease the number of cars on the road without inconveniencing the people who need to drive.
Let's face it, while cars are a big source of pollution, they are a necessary evil for a variety of reasons and a ban would create issues for people who need them. Other options such as incentives for using public transit should be trid first in an attempt to curb the use of cars in the city.