The UPSC Prelims exam is divided into two papers: General Studies Paper-I and General Studies Paper-II. The History syllabus for UPSC Prelims is a part of General Studies Paper-I. The History syllabus for UPSC Prelims covers ancient, medieval, and modern Indian history. Below are the chapter-wise topics for History in UPSC Prelims:

1. Ancient India - Prehistoric period, Indus Valley Civilization, Vedic period, Mauryan Empire, Gupta Empire, post-Gupta period.
2. Medieval India - Delhi Sultanate, Mughal Empire, Vijayanagara Empire, Maratha Empire, Bhakti and Sufi movements, emergence of regional states.
3. Modern India - British East India Company, Governor-Generals and Viceroys, Revolt of 1857, Indian National Congress, Swadeshi movement, Non-Cooperation and Civil Disobedience movements, Partition and Independence.

It is important to note that the History syllabus for UPSC Prelims is not limited to these chapter-wise topics only. The syllabus also includes aspects of culture, art, architecture, and literature from ancient, medieval, and modern India. Additionally, current events related to History may also be asked in the exam.

In order to prepare for the History section of UPSC Prelims, it is recommended to refer to NCERT textbooks from Class VI to XII, and also to read standard reference books on Indian History. It is also important to practice previous year question papers and take mock tests to assess one’s preparation level.