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