History:

1. New-NCERT, TN-Class:11/12, NIOS (Free)
2. History of Modern India - Bipan Chandra
3. Spectrum Modern History 
4. India's Struggle For Independence - Bipan Chandra 
5. India's Ancient Past - R.S. Sharma 
6. History of Medieval India - Satish Chandra

Geography:

1. NCERT (Class 6th to 12th)
2. Certificate Physical and Human Geography - Goh Cheng Leong 
3. Geography - A Comprehensive Study - Mahesh Kumar Barnwal 
4. Geography NCERT class VI to Class XII 
5. Oxford School Atlas – Oxford

Environment:

1. NIOS (Environment biodiversity) & NCERT
2. Science and Technology by Ravi Agrahari (Mcgraw-hill)
3. Last Six Chapters of 12th Class NCERT
4. India Year Book

Indian Polity:

1. Lakshmikant
2. Constitution of India
3. PRSIndia.org: latest Bills & Amendments

Economy:

1. Budget & Economic Survey
2. Indian Economy - Ramesh Singh
3. India Year Book

General Science

1. Lucent General Science
2. Science Subject NCERTs

Current Affairs

1. Any Newspaper like The Hindu or The Indian Express
2. Monthly Magazine  
3. 10Pointer Daily Current Affairs