Case studies are often used in exams to test a candidate's analytical and problem-solving skills. While specific case studies covered in previous exams may vary, here are some examples of case studies that have been used in the past:

1. Case Study on Environmental Pollution:
This case study may involve analyzing the causes and effects of pollution in a particular region. Candidates may be required to identify the sources of pollution, assess its impact on the environment and human health, and propose strategies to mitigate the pollution problem.

2. Case Study on Economic Development:
In this case study, candidates may be presented with a scenario where a country or region is experiencing challenges in achieving sustainable economic development. They may be asked to analyze the reasons for the economic challenges, propose measures to promote economic growth, and evaluate the potential impact of these measures on various stakeholders.

3. Case Study on Public Health Crisis:
This case study may revolve around a public health crisis such as a disease outbreak or a healthcare system failure. Candidates may be required to analyze the causes of the crisis, suggest immediate and long-term measures to address it, and assess the role of various stakeholders in managing the crisis effectively.

4. Case Study on Urban Planning:
Candidates may be presented with a case study related to urban planning challenges in a specific city or region. They may need to analyze issues such as congestion, inadequate infrastructure, and lack of affordable housing. Candidates may be asked to propose solutions to improve urban planning and ensure sustainable development in the area.

5. Case Study on Social Justice:
In this case study, candidates may be required to analyze a situation where there are issues related to social inequality, discrimination, or injustice. They may need to identify the root causes of these problems, propose measures to address them, and evaluate the potential impact of these measures on marginalized communities.

These are just a few examples of case studies that have been covered in previous exams. It is important to note that the specific details and context of each case study may vary, but the overall objective is to assess a candidate's ability to analyze complex situations, think critically, and propose effective solutions.