Introduction:
In the UPSC examination hall, candidates are often required to bring specific tools and materials for certain papers. Paper II, commonly known as the Civil Services Aptitude Test (CSAT), is a paper that assesses a candidate's aptitude and analytical skills. In this paper, candidates are not allowed to bring rulers or geometrical instruments. Let's delve into the reasons behind this rule.

Reasons for not allowing rulers or geometrical instruments:
There are several reasons why the UPSC does not permit the use of rulers or geometrical instruments in the examination hall for Paper II.

1. Fairness and Uniformity:
UPSC aims to conduct a fair and uniform examination for all candidates. Allowing certain candidates to use rulers or geometrical instruments while others do not have access to them would create an unfair advantage for some. Therefore, to maintain the integrity of the examination, these tools are not allowed.

2. Focus on Aptitude and Analytical Skills:
The CSAT paper primarily focuses on evaluating a candidate's aptitude and analytical skills. By not permitting rulers or geometrical instruments, the UPSC intends to assess a candidate's ability to perform calculations, measurements, and estimations without relying on external tools. This enables the UPSC to gauge the candidate's true aptitude and analytical prowess.

3. Time Management:
Another factor to consider is time management. Allowing rulers or geometrical instruments may lead to candidates spending unnecessary time on precise measurements or drawings, which can hinder their ability to complete the paper within the given time frame. By excluding these tools, the UPSC ensures that candidates utilize their time efficiently and focus on answering the questions effectively.

Conclusion:
To maintain fairness, assess aptitude and analytical skills, and encourage efficient time management, the UPSC does not permit the use of rulers or geometrical instruments in the examination hall for Paper II. Candidates are advised to familiarize themselves with the rules and regulations provided by the UPSC to ensure a smooth and successful examination experience.