Hello,

Apart from NCERT books, now, there are standard textbooks which will be extremely useful for IAS aspirants to crack the exam.

Indian Polity and Constitution :

• Indian Polity – by M. Laxmikanth
• Important Acts that Transformed India – by Alex Andrews George
• Important Judgments that Transformed India – by Alex Andrews George

History :

• India’s Struggle for Independence – Bipan Chandra
• Facets of Indian Culture – Spectrum
• Ancient and Medieval India – by Poonam Dalal Dahiya

Geography;

• Certificate Physical And Human Geography – by Goh Cheng Leong
• Geography of India – by Majid Husain
• Oxford Student Atlas for India

Science and Technology – by Ravi P. Agrahari.

Environment – By Shankar IAS

India 2020 Yearbook – by Rajiv Mehrishi

The Malayala Manorama English Yearbook 2020 – by Mammen Mathew

These books are for your UPSC preliminary examination.

Hope this helps!!