Landfill is a sub topic of your geography studies of waste and pollution and the GCSE syllabus requires that you show an understanding of similarities and differences between the production and handling of a variety of waste products and pollution. You also need, as usual, to be aware of the differences between the richer and poorer countries.
The quantity of waste and pollution varies between countries. In the richer countries, consumerism is much greater as the population has a higher disposable income. As a result, they produce a lot of waste that goes into landfill sites. The UK produces over 500 kg of waste per person per year where poorer countries like Estonia and Poland produce only half of that. The world's poorest countries produce only about 100 kg of waste per person per year.