Formal pairs suit Writing Task 2. Neutral ones work anywhere. Informal ones belong in Speaking.
1.urban sprawl
formalthe uncontrolled spread of a city into the countryside
Urban sprawl increases car use because homes are far from shops and offices.
Limit, curb and contain collocate with it.
2.affordable housing
neutralhomes that people on average incomes can afford
There is a severe shortage of affordable housing in most capital cities.
Provide and build collocate with it.
3.the cost of living
neutralthe money needed to pay for basic things such as food and rent
The cost of living in London is much higher than in other British cities.
The cost of living is high, not expensive.
Avoid: the living cost is expensive → the cost of living
4.overcrowded cities
neutralcities with too many people for the space and services
Overcrowded cities struggle to provide enough school places.
Overcrowding is the noun.
5.green spaces
neutralparks and other areas of grass and trees in a town
Green spaces improve residents' mental health.
Protect and create collocate with it.
6.high-rise buildings
neutralvery tall buildings with many floors
Building high-rise buildings is one way to house more people on less land.
Tower blocks is the British term for high-rise flats.
7.run-down neighbourhoods
neutralareas in poor condition because of neglect
Investment in run-down neighbourhoods can reduce crime.
British spelling: neighbourhood.
8.urban regeneration
formalimproving old or poor areas of a city
Urban regeneration projects turned the old docks into homes and offices.
Regeneration project and regeneration scheme are natural partners.
9.soaring rents
neutralrents rising very quickly
Soaring rents are forcing young people to live with their parents for longer.
Soaring also goes with prices and costs.
10.get on the property ladder
informalbuy your first home
It is much harder to get on the property ladder now than in my parents' day.
British and informal; good in Speaking. In Writing, use buy their first home.
11.residential areas
neutralparts of a town where people live rather than work
Heavy lorries should be kept out of residential areas.
Commercial and industrial areas are the contrasts.
12.local amenities
formaluseful places nearby, such as shops, parks and libraries
New housing estates often lack local amenities.
Access to amenities is another natural phrase.
13.city dwellers
formalpeople who live in a city
Many city dwellers rarely see the night sky because of light pollution.
Urban residents is a neutral alternative.
14.put pressure on infrastructure
formalmake roads, water and transport struggle to cope
Rapid population growth puts pressure on infrastructure such as water supply.
Put a strain on is an alternative.
15.noise pollution
neutralharmful or annoying levels of noise
Noise pollution from traffic disturbs sleep in inner-city flats.
Reduce and suffer from collocate with it.