1. Bicycles are generally cleaner than both motorbikes and cars.
2. Motorbikes are dirtier than bicycles but cleaner than cars.
3. Among the three, cars are the dirtiest mode of transport in cities.
4. Bicycles are the most eco-friendly option compared to motorbikes and cars.
5. Motorbikes are faster than bicycles but not as fast as cars on city roads.