Pollution Caused by Buses
Buses may contribute to atmospheric and noise pollution in cities. The principal reasons for pollution caused by buses are poor vehicle maintenance, inadequate enforcement of rules and regulations, and inappropriate vehicle type and size.

Poorly maintained buses use more fuel and emit excessive exhaust. This is a common problem where maintenance standards, and exhaust emission standards, are not set and enforced. It is compounded where the number of vehicles in the system is excessive, or where many small vehicles are used instead of fewer large buses.