the time when a lot of people are travelling to or from work and so roads and trains are very busy
rush hour
air pollution in a city that is a mixture of smoke, gases and chemical
smog
describe a city or an area in the world which is poorer and has less advanced industries
developing
someone who travels regular between work and home
commuter
situation when something is full or blocked, especially with traffic
congestion
money that you pay to use a bridge or road
toll
not at the most popular and expensive time
off-peak
describe a city or an area with an advanced level of technology, industry
developed